Class Of Achievers

Motion of no confidence

2018-07-20T23:18:00.000-07:00

A motion of no-confidence(non-confidence motion) (alternatively vote of no confidence, no-confidence motion, or (unsuccessful) confidence motion) is a statement or vote which states that a person(s) in a position of responsibility (government, managerial, etc.) is no longer deemed fit to hold that position, perhaps because they are inadequate in some respect, are failing to carry out obligations, or are making decisions that other members feel detrimental.

As a parliamentary motion ,it demonstrates to the head of state that the elected parliament no longer has confidence in (one or more members of) the appointed Government.

The Article 75, Part 5( The Union) says that the Council of Ministers shall be collectively responsible to the Loksabha, which means that the ministery actually stays in office as long as it enjoys the confidence of majority of members of loksabha, which deduces that the government shall stay in power as long as it enjoys the confidence of Majority of Members in lok sabha.

Some Facts

No-Confidence Motion can only be introduced in Loksabha.

The motions needs support of atleast 50 members of the house to be admitted for discussion.

In case the motion carries forward, the house debates and votes in the motion, the voting is done by simple Majority process.

As of now a total of 26 No-Confidence Motion has been tabled in Loksabha.

First No-Confidence was tabled by Acharya Kriplani in 1963.

Prime Minister Indira Gandhi faced the maximum no confidence Motion being in office.

Also by introduction of Anti-Defection law by 52nd constitution Amendment act of 1985, the No-Confidence Motion is useless if the Ruling party has an absolute Majority in Parliament.

Censure motion

A censure motion is different from a no-confidence motion. Depending on the constitution of the body concerned, "No Confidence" may lead to dismissal of the council of ministers or other positions-holders ,whereas "Censure" is meant to show disapproval and does not result in the resignation of ministers. The censure motion can be against an individual minister or a group of ministers, but the no-confidence motion is directed against the entire cabinet. Again, depending on the applicable rules, censure motions may need to state the reasons for the motion while no-confidence motions may not require reasons to be specified.

Difference between Censure motion and Motion of No Confidence

>In case of censure motion, reasons must be stated for its adoption in the Lok Sabha while in case of motion of no confidence no such reasons for its adoption are required to be stated in the Lok Sabha.

>No confidence motion can only be moved against the entire council of ministers while censure motion can be moved against an individual minister, a group of ministers and the entire council of ministers.

>Censure motion is moved for censuring the council of ministers for specific policies and action and no confidence motion on the other hand, is moved for ascertaining the confidence of Lok Sabha in the council of ministers.

>The council of ministers need not resign from the office if censure motion is passed in the Lok Sabha while in case of motion of no confidence, the council of minister must resign from office if the motion is passed.

Hope this article help you .

Atom

2018-04-08T09:08:00.001-07:00

Hello Students,

Today we are going to cover the topic “Atom”.

What we are going to cover in this article:

1. What is atom?

2. Who discovered the atom?

3. Structure of atom.

So, first of all what is atom and where it exist.

Atoms are the basic units of matter.

Who discovered it?

The idea that matter is made up of discrete units is a very old idea, appearing in many ancient cultures such as Greece and India. The word "atom" was coined by the ancient Greek philosophers Leucippus and his pupil Democritus.

The constituents of the atom.

The constituents of the atom are protons, neutrons and electrons. The protons and neutrons (nucleons) are found in the nucleus of atoms. The nucleus of an atom is surrounded by empty space in which there are electrons.

Particle: Proton

Relative Mass: 1

Relative Charge: +1

Charge/C: 1.674929 x 10^-19

Mass/kg: 1.674929 x 10^-27

Particle: Neutron

Relative Mass: 1

Relative Charge: Neutral

Charge/C: 0

Mass/kg: 1.674929 x 10^-27

Particle: Electron

Relative Mass: 0.0005

Relative Charge: -1

Charge/C: -1.674929 x 10^-19

Mass/kg: 9.1×10^-31

Atoms are described by their proton number (Z), which is the number of protons they contain.

Isotopes are atoms which have the same number of protons but different numbers of neutrons. Isotopes are all atoms of the same element. We can see below that uranium-238 still has 92 protons but it now has 146 neutrons so its nucleon number is now 238.

Isobars are atoms of different Chemical elements that have the same number of nucleons.

Medical Uses of Isotopes

isotopes are widely used in medicine to diagnose and treat illnesses. Isotopes have extensive applications in bio-medical research and other fields like chemistry, physics, biology, and geo-sciences.There are many radioisotopes which are mainly used in the treatment of hazardous diseases such as cobalt-60 ( Co-60) is used to damage the cancer cells without surgery , that is known as radiotherapy.

Uses of Isotopes in Agriculture

They are used to cause mutation in insects that make them sterile or to cause death. This method helps in pest control in agriculture.

Uses of isobar

an isobar of iodine is used in the treatment of goitre.

an isobar of cobalt is used in treatment of cancer.

an isobar of uranium is used as a nuclear reactor

Atomic Number

The atomic number (symbol Z) of a chemical element is the number of protons found in the nucleus of an atom.

Element	Symbol	Atomic Number	Atomic Mass	Number of Protons	Number of Neutrons
Hydrogen	H	1	1	1	0
Helium	He	2	4	2	2
Lithium	Li	3	7	3	4
Beryllium	Be	4	9	4	9
Boron	B	5	11	5	6
Carbon	C	6	12	6	6
Nitrogen	N	7	14	7	7
Oxygen	O	8	16	8	8
Fluorine	F	9	18	9	9
Neon	Ne	10	20	10	20
Sodium	Na	11	23	11	12
Magnesium	Mg	12	24	12	12
Aluminum	Al	13	27	13	14
Silicon	Si	14	28	14	14
Phosphorous	P	15	31	15	16
Sulphur	S	16	32	16	16
Chlorine	Cl	17	35	17	16
Argon	Ar	18	40	18	22
Potassium	K	19	39	19	20
Calcium	Ca	20	40	20	20

Atomic Mass

It is approximately equivalent to the sum of protons and neutrons of the atom.

What is Accounting?

2018-04-06T01:46:00.000-07:00

What is Accounting?

It is the science to record the transactions. It is also art to transfer the values from bill, vouchers, invoices, receipts and cash memo to day book. We can explain accounting as the system of scientific recording which is used for calculating the net profit from all the transaction. Whole accounting system is worked on the following accounting equation.

Assets = Capital + Liability

What is the definition of Accounting?

To record financial transaction is accounting.

In accounting, transaction is the contract between buyer and seller for buying and selling of goods, asset or service. It is also exchange of money from one party to other party when goods and services are bought and sold on credit. It means when we buy the goods, it is the transaction. When we sell the goods, it is the transaction. When we get any service, it is the transaction. When we provide the service, it is the transaction.

What is the simple definition of Accounting?

Ans. Journal → Ledger → Trial Balance → Manufacturing Accounts → Trading Accounting → Profit and loss accounting → Balance sheet → Cost Sheets → Budgets → Trends → Ratios → Cash flow statements → fund flow statement

History of Accounting

Like any other invention, accounting is the invention of India because sufficient evidence exists to lead one to conclude that the art and practice of accounting, as a highly developed system, was in India even during the times of the Vedas. There are lots of direction in the Vedas for getting success in the trade. One of them is to record each transaction like recording any other text. Because Indians had complete knowledge of accounting, so they taught accounting to the other country's trade. We know that we had the trade with Africa. We sold many things to Africa and obtained the Gold. We had taught them to record each transaction for success in the business.

Branches of Accounting

Accounting is just like a tree. Financial accounting, cost accounting, corporate accounting and management accounting are its main branches.

Accounting Software

Today, accounting records are kept with the help of accounting software. There are lots of software companies who sell accounting software in the market. You can choose anyone from them. We are providing you the top list of accounting software in the market. You should also study the list of accounting software mistakes.

NOT BACK-UPS

This is the first accounting software mistake which are done in accounting departments. When accounting department completes his voucher entries in accounting software, they feel safe.

This is the mistake because all accounting software has the system and which is done by some codes which knows the computer programmer. So, it may be crashed. It may be delete your all database in one second. At that time, you will pay big fees to computer programmer for restore his database because there are lots of useful accounting information in your database.
There are lots of natural disaster which may destruct your all accounting software data. For example, in India, previous year, we see big flood in Uttrakhand and this year, we see big flood in Jammu and Kashmir. So, if you have the branch in this area and you did not back-up your accounting software data, you will unable to restore it from your other branches or from cloud.

So, better is make the good time table of back-ups of your accounting software database. You can back up daily, weekly or monthly as per the quantity of data entry.

NOT PROFESSIONALS

Few years ago, I had obtained a query from a computer programmer who is developing a special accounting software for a company. He is getting my advice relating to process of any special accounting function. I suggested. So, he developed same. Now, same software is working by whole company. If I am not professional in accounting area, my wrong suggestion will make wrong accounting software and no one can save from this mistake even there is CA who will record in same default accounting software. My main aim of teaching that you should not hire any person who is not professional of accounting. It means not to go cheap accountants but get quality service from great accounting professionals.

NOT UPGRADE

Time to time, accounting software companies updates their accounting software. You just switch to its upgrade version. But you are lazy or you do not want to invest more money in its upgrade version but it increases your cost because when you will use not upgraded accounting software, there is more chance it may be corrupted or showing errors during accounting record.

NOT TRAINING

In this world, everything is changing fastly. So, due to changing of business system, accounting softwares are also changing fastly. If your business has to run fast and catch all the changes, it has to accept all changes in accounting system as challenge. As businessperson, you should give training to your accounting department employees. If you are saving your money by not providing training relating to latest in accounting software, it is your big mistake because untrained employee will do more mistake if you update the accounting software but did not manage the training relating to such updates.

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Economics of Education

2018-04-04T23:50:00.001-07:00

Economics of Education

Education as an Investment in Human Capital

Human capital is the skills, training, education, knowledge, and ability possessed by workers. Education and training are means of developing human capital.

Skilled workers are those with lots of human capital; unskilled workers possess little human capital. Skilled workers receive a higher wage than unskilled workers because

(1) skilled workers have produce more valuable output than unskilled workers and

(2) the supply of skilled workers is smaller than the supply of unskilled workers.

Spending on Education

Most of the benefits from education are private benefits: better educated workers receive higher wages. So why is K-12 education publicly funded?

external benefits of education:

less likely to commit crime
less likely to be on welfare
more likely to be productive citizens who pay more in taxes than they collect in government benefits
diversity in the classroom may foster social stability

Higher Education

Why is college so much more costly than elementary and secondary education?

College professors are paid more than elementary and secondary school teachers. College professors also teach less than elementary and secondary school teachers. Colleges have expensive libraries and laboratories.

School Reform

merit pay and tenure for teachers

teachers tend to be paid solely on the basis of education and seniority
cannot be fired after they have taught for a set number of years
when pay is not based on performance, there is an incentive to do as little as possible
tenure adds to the lack of performance incentives for older teachers

Teacher unions argue that teachers work to the best of their ability at all times and that letting principals hand out merit raises and fire bad teachers would foster cronyism. Besides, the pay of teachers is low in general.

Poverty in America

Measuring Poverty

A country's measure of poverty must compare relative income levels within that country. For example, someone who is comfortable in Ethiopia would be considered impoverished in the U.S.

In 2003, the poverty level for a family of 4 (2 adults and 2 children)was $18,660. About 35.9 million U.S. residents live below the poverty line. The poverty rate is 12.5%.

The percentage of poor people fell a lot during the 1960's and early 1970's. The record low poverty rate was 11.1% in 1973. It rose in the late 1970's but has fallen since.

Who are the Poor?

The incidence of poverty is unequally distributed among sections of society.

the highest incidence of poverty occurs among those who are under age 18: 17.6% (the poverty rate for those over 65, 10.2%, is less than that for those age 18 to 64)
the incidence of poverty is much higher among blacks (24.4%) and Hispanics (22.5%) than it is among whites (8.2%)
the poverty rate among married couples is 5.4% while the poverty rate among female headed households is 28.0%

Causes of Poverty

lack of a job - accounts for 3/4th of those in poverty
place of residence - 2/3 of the poor live in big cities; 1/3 live in rural areas
lack of education - 25% of the people with less than 8 years of schooling live in poverty

Programs to Help the Poor

Social insurance programs are designed to replace the lost income of those who worked but are now retired or disabled. Social security and Medicare are the major social insurance programs.

Income assistance programs provide money and in-kind benefits to the poor.

Temporary Assistance to Needy Families
Supplemental Security Income (SSI)
Medicaid
food stamps

Welfare Reform

those who receive welfare benefits lose the incentive to return to work
those who grew up on welfare become dependent on welfare into adulthood and consider it a "right"

Before 1996, 35 states had some form of workfare: require welfare recipients to accept public service jobs or participate in job training

1996 Personal Responsibility and Work Reconciliation Act:

replaced AFDC with TANF
lifetime 5 year limit that a recipient can be on welfare
people on welfare for 2 years must participate in welfare to work program
limits benefits for noncitizens and teenage mothers not living at home
states must be more aggressive in enforcing child support payments from fathers

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Introduction to Computer Systems

2018-04-03T23:12:00.002-07:00

Introduction to Computer Systems

A system is contained within a boundary, either physical or logical. Outside the boundary is the environment, which the system interacts with via inputs and outputs. The system has no direct control over the environment, it can only control what happens inside the boundary. The system receives inputs, but has no control over what these inputs are. It gives outputs but has no control over what then happens to them.

Systems can be defined in many ways. They could have the same boundary, but a different way of looking at it. It could also have a different boundary. For example, you could look at a computer system in the following ways:

A tool that takes commands and returns data
A collection of components that take in electrical signals and returns electrical signals
A device for converting characters to binary code
A component in an office workflow diagram

A system is analogous to mathematical relations. A system maps inputs to outputs. This is an abstraction level which is sufficient for many purposes.

Systems are nested, therefore decomposition is normally a good way to study a system. Systems can "overlap" (at least logically). Definitions can be applied to all systems.

To design a system:

1. Determine boundary

o What can be changed

o What is in the scope of design, what is outside

2. Determine the interfaces/how it interacts with the environment

3. Determine mapping relations

4. Determine what internal data is required to support mappings

o Data storage

To design a system to work into an existing system, you need to think of separate components. Each component contains a boundary and an interface, and I/O mappings. How the system works should be transparent to each other module. All you need to know is:

How to use the interfaces (I/O structures)
What the mappings achieve
How trustworthy the components are

Hierarchies

Systems are hierarchical structures. Each level is a component of a higher level, and each component also has components at lower levels. Some components and levels are logical. Each topic in Computer Science tries to deal with one level at a time. Mixing levels of hierarchy can lead to confusion.

Science and Engineering

Science explores the physics of computing, i.e., what happens in energy terms, what the components are and why they behave as they do and the theory underpinning hardware and software.

Engineering studies ways to build systems. It looks at the hardware and software, and the network and systems architectures.

Generalisation of Engineering

Engineering principles in one area usually apply in some form in other areas (one principle can be applied to, say, civil engineering, just as much as CS). For example, good practice in development, documentation and testing principles, the planning and management, dealing with cost effectiveness and professional oversight are all traits of engineers.

Students rarely meet reality, however engineering is based in reality. Reality is big, messy and imprecise. Reality changes goals and resources during projects, demands evidence of performance and wants things to last forever (but then discards them the following week).

As reality is often too much for engineers to conceive, they simplify it using models. Models are representations of reality. Programs, diagrams, mathematical definitions, CAD, working scale models are all examples of models. Models are used to abstract away detail that is not relevant to the current purpose. Models can be static (diagrams, maths, etc) or dynamic (programs, train layouts, animated CAD drawings, etc).

Lifecycles

All engineering projects can be characterised in general terms:

Requirements
Specifications
Designs
Implementations
Testing
Maintenance
Decommission

We will briefly look at each. You should apply these principles in other modules. There are lots of lifecycle models (waterfall, spiral, etc) that can be used. Lifecycles are abstract summaries of a chaotic reality - don't expect models to be perfect, but they shouldn't be dismissed either.

Development methods are different to lifecycles. The methods are practical help with the development based on expertise/experience of experts.

Requirements

This is what the system is required to do. This is a constraint also - you should not be making the system do things that is beyond the requirements. Requirements are quite general, as this is looking at the system from a high level. At lower levels, requirements are more specific to a particular architecture, platform, etc...

Testing happens against the requirements, therefore the requirements need to be objective and clear. Requirements also change, and these changes must be documented. Engineers aim to just meet the requirements; extras are not needed, or in some cases desired.

Specification

A specification is a contact for a development. It meets the requirements and is an abstract description of the requirements - it is not how the requirements are going to be achieved. It could use diagrams, mathematics or logical analysis. It needs to be rigorous and unambiguous. It should be checked against the requirements.

VVC (Verification, Validation and Certification)

Verification - This checks that the data is factually correct.
Validation - This checks that the data fits in with it's intended use.
Certification - The checks a system against external documentation and operational standards.

Design

This is less abstract than a specification, however still does not contain any code. There may be different design at different levels. A design also adds more constraints.

Implementation

This must match the design. It also includes documentation - both of the development and for the users. Implementation is a trivial stage compared to the specification and designs, if they are done right.

Some tips for implementation are:

Re-use code where ever possible
Document the original or re-used code
Document all change and the rationale behind those changes to re-used code.
Write re-usable code
Use a good style of coding and document your coding fully
Document how procedures and packages are used
Document what each component does and the conditions they take.

Testing

This is the most important part. It is dependent on the earlier parts and consists of various parts:

Unit tests - this tests the internal code
Module, integration and system tests - testing the individual components and composition verification
Acceptance or certification testing - validation that works as intended in context and within standards

Testing reveals errors, not correctness; it is impossible to show a program is perfect. Tests should be designed to break the system; you should always be testing for unexpected things (e.g., illegal inputs, out-of-range data). Testing should occur close to or on the boundary of the operational envelope.

The specification and design should be used to identify meaningful tests.

Maintain

Most systems change after delivery, perhaps a new platform is introduced, etc... Bug fixes may also need to be applied. Documentation and code needs to be maintained..

Regression testing should be performed.

Work out what tests should and should not still work
Run all your tests again and check the results
Don't just test the changed parts.

Decommission

Few systems are ever thrown away. If a system is used, it is likely to be replaced. You should try to reuse and recycle. There could be lessons to be learnt from an old system, requirements and scenarios could be similar to the new system, components might need to be retained and each of these elements requires careful analysis.

Documentation is crucial

Computer Hierarchy

A computer is a hierarchy of parts (a system). There are many overlapping hierarchies and views, logical and physical views are both hierarchical and you can look at things from both a functional and architectural point of view. ICS only covers some of the views and hierarchies that exist.

Events

Any input is an event. A command or data sent may change the system state. How an event is determined depends on your view, for example from the view of the CPU only electrical pulses are valid. Logically this could be a single character, a signal, etc... From a human view, this could be a string of text, or a whole mouse movement (which relates to multiple signals).

Keyboard Events

A keypress sends electrical signals to a keyboard transducer. The transducer converts the character pressed to an IRA (ASCII) bit value.

Mouse Event

Press, release, etc are all considered individual mouse events. The window manager interprets events and movements to commands. Commands are interpreted to machine instructions in the form of bits.

Bits are transmitted to the I/O module and memory. Transmission of input is identical for all bits. In a window, a window manager interprets key presses and mouse movements to machine instructions or data.

A filename is a logical reference to a distributed set of addresses. Physically this is an index address and lots of separate data blocks.

A computer takes well formed commands and then uses context to deduce what's intended.

Views and Levels

There are different ways you can look at things:

Internals - above the hardware level but below the operating system
Architecture - how the programmer sees the system
Organisation - how features are laid out

Architecture

Data representation
Instruction set
Addressing
I/O mechanisms

Most of these are logical abstractions. Physical signals represent bits and they represent instructions and addresses

Organisation

· Internal signals, clocks and controllers

· Memory addressing

· Instructions

· Hardware support

Structures and Functions

Structure	Functions
CPU	storage
Memory	processing
I/O	movement
communications	control

· control unit - controls execution cycle

· ALU - computational core

· registers - internal memory

· connections - connections between other units

IAS

John von Neumann was at the Princeton Institute for Advanced Studies (IAS). He came up with the theory for a stored-program computer in about 1945. The first IAS machine was completed in 1952. Although this is later than Turing's efforts in the 1940's, the IAS system was public and open from inception so became more well known.

The IAS architecture stored data and instructions in a single read/write memory. The memory contents were addressable by locations and sequential execution from one instruction to the next occurred.

Main Memory

Main memory is a collection of locations, each holding a binary value. Instructions are stored and read sequentially in one set of addresses. A logical abstraction of this is a stack. All locations have sequential identities (addresses) which data is stored and accessed by.

Architecture functions and organisation are built round groups of addresses.

instruction	0
instruction	1
instruction	2
instruction	.
instruction	.
instruction	x
data	x+1
data	x+2
data	.
data	.
data	n-1
data	n

Main memory has n locations. Instructions are in locations 0-x. The instruction stack is a logical data structure with input at the top, and reads happen at the top too.

Words and Bits

Each memory location is 1 word. The IAS machine had 1000 words in memory. The Intel 8088 (1979) had 1 MB. The current Pentium 4 (IA32) architecture has 64 GB of words.

Each word contains a fixed number of bits. The IAS had 40-bits words, but most modern systems have 2ⁿ bits, for example, Intel processors until the 386 had 16 bit words. Early Pentium's had 32 bit words and the Pentium II onwards had 64 bit words.

There are many formats for a word. The simplest is the opcode followed by an operand. The opcode identifies one machine instruction (operation). The operand is the address of data to be operated on.

Fetch-Execute Cycle

Computer operations are in a series of cycles. For example, retrieve a word from main memory, execute instruction in a word, etc..

Instructions locations number logically from 0. When the computer systems, a program counter (pc) is set (i.e., to 0). This causes the 0th instruction to be fetched. Instruction is then executed and the pc is incremented. The first instruction is executed next. The fetched instruction is written to the instruction register (ir) for execution.

The pc and ir are CPU registers, like main memory, but fast and inside the CPU. pc and ir are CPU registers. The pc only needs to hold an address. CPU buffers are common, for example, between the pc, ir and main memory. Buffers could include the mar (memory address register) and the mbr (memory buffer register)

The CPU control unit determines when to fetch an instruction. The communication between the main memory and the CPU uses buses for addresses, control signals and data. The control uses a clock tick (this is a regular pulse signal). The control units ticks to start the next element of the F-E cycle.

Fetched instructions might need more memory interaction because an execution can take place - this is an indirect cycle.

The execution that occurs depends on the instruction in the ir. For example, it could be

· moving data among registers, from CPU to main memory, etc

· modifying control

· I/O

· ALU invocation

Interruptions

Assume end-to-end execution of stored programs. The CPU is very efficient compared to other peripherals and the F-E cycle is faster than other devices. Rather than the CPU hanging and waiting for a device, interruptions allow the CPU to continue with another instruction and return to one that's waiting on a device when the interrupt is called.

Different types of interrupts exist:

· Program Interrupts - Illegal processing attempted (for example, a divide by 0, arithmetic overflow or an illegal memory call)

· Timer Interrupts - Allow regular functions to occur (housekeeping, polling for data, etc)

· Device Interrupts - Come from device controllers, such as I/O. These signals could be such as "ready", "error", etc.

· Hardware Failure Interrupts - Power out, memory parity error, etc.

Device Handling

A processor fetches an instructiowww.n which involves a device call. The execution calls a set-up program (I/O program) which prepares buffers for data, etc... The device driver (an I/O command) is then called and the execution terminates.

Preparing for an Interrupt Cycle

This is a variant of the fetch cycle. The current pc is stored in a dedicated address. After the interrupt is completed, the control unit reads the stored pc value and resumes at that location.

The CPU knows addresses to be used. The interrupt only starts when the previous instruction is fully executed.

Interrupt Handling

Any device may send an interrupt (signalling that it is ready for I/O, etc), however the handling details are specific - it might include the OS for example.

Computer Connections

Devices inside a computer are connected using buses, lines and interfaces.

There are many different types of connections - point-to-point (a dedicated link) or a bus (a link shared by many components). A bus corresponds to a particular traffic type - data, addresses, etc...

Networking can be wired or wireless. Conceptually it is different to internal communications, but physically it is becoming similar to buses. Bus and network protocols are slowly converging.

Internal and external communications have different emphases. Networking has an emphasis on security, whereas buses tend to emphasise robustness.

Buses link at least two components, and traffic is available to all logical components connected to that bus. Logically, a bus is dedicated to either data, addresses or control signals. Physically, a bus comprises of a bundle of separate bus lines.

Buses are things passing values - like a flow of communications. In reality, it carries current, so has values at all points simultaneously - logically this is either 1 or 0. Unfortunately transfer isn't really instant (assuming that it is is a level of abstraction). A pulse that is either on or off doesn't exist in the real world. There is a leading edge and a trailing edge as voltage rises or falls. These edges don't carry any data and signals are not relevant here.

Buses use serial communications, i.e., 1 bit at a time. There are 8 lines for an 8 bit bus.

Parallel buses are buses of serial lines. Each bus still carries one thing, but a communication may be split over many buses. In theory, parallel is faster and more efficient, however serial buses tend to have higher data rates due to the overhead of parallel (assembly and disassembly of packets).

Early buses had separated, unsynchronised clocks - CPU time was wasted waiting for devices to catch up. Modern buses are controlled by a single CPU clock, however, variable speeds are being re-introduced according to application.

Data Bus and Lines

Data buses have one bus line per bit in a word (or multiples of this), e.g., 32-bit words have 32 (or a multiple of this) data lines, each requiring its own connection pin.

Address Bus and Lines

Buses may have a memory-I/O split. Most significant bit may say whether it's intended for memory or an I/O address.

Control Bus and Lines

These are normally sufficient with 1 bit. They carry things such as timing signals (clock/reset), command signals and interrupt signals.

Modules and Interfaces

Each computer component is a module with an interface. It is based on the engineering principle of each module being self-contained with minimal interfaces. This is true of modules in any other engineering (software, etc)

Memory Interface

The memory interface passes fixed length words to the memory. The memory doesn't care what it's storing, it could be an address or data, or anything.

Control signals (read signal, write signal) tell the memory module what to do, the address bus carries the address that's being considered, and the data bus will either carry the contents of the memory to or from the memory.

CPU module

The CPU is "intelligent". It identifies the content of the data bus to be different types and deals with them accordingly.

Coming in, it has control signals (interrupts) and data signals (instructions and data). Going out it gives out control signals, addresses and data.

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What is development?

2018-04-03T00:16:00.002-07:00

What is development?

Development conveys the ideas of improvement, progress, well being and aspiration for a better society.

development is defined in narrower terms also like increasing growth rate or modernising the society. Modernising the society means having dams, opening industries , having many brands etc.

but development has a broader meaning as well. there needs to be improvement in the lives of people. Poverty needs to be reduced, health of people needs to be improved and employment opportunities need to be given.

Jawaharlal Nehru had said, “these new and revolutionary changes in China and India, even though they differ in content, symbolize the new spirit of Asia and new vitality which is finding expression in the countries in Asia. ”All the three countries had started planning their development strategies in similar ways. While India announced its first Five Year Plan for1951-56, Pakistan announced its first five year plan, called, the Medium Term Plan, in 1956. China announced its First Five Year Plan in 1953. Till 1998 ,Pakistan had eight five year plans whereas China’s tenth five year period is 2001-06. The current planning in India is based on Tenth Five Year Plan(2002-07). India and Pakistan adopted similar strategies such as creating a large public sector and raising public expenditure on social development. Till the 1980s, all the three countries had similar growth rates and per capita incomes. Where do they stand today in comparison to one another? Before we answer this question let us trace the historical path of developmental policies in China and Pakistan. After studying the last three units, we already know what policies India has been adopting since its independence.

Development Strategies of India, China and Pakistan

India, China, Pakistan have many similarities in their development strategies which are as follows

(i) India, Pakistan and China have started towards their developmental path at the same time. India and Pakistan became independent nations in 1947. While Peoples Republic of China was established in 1949.

(ii) All the three countries had started planning their development strategies in similar ways. India announced its Five Year Plan in 1951-56, while ’ Pakistan announced its first Five Year Plan in 1956, which is called Medium Term plan. China announced its First Five Year Plan in 1953.

(iii) India and Pakistan adopted similar strategies such as creating a large public sector and raising public expenditure on social development.

(iv) Till the 1980s, all the three countries had similar growth rates and per capita incomes.

(v) Economic reforms took place in all the three countries. Reforms started in India in 1991, in China in 1978 and in Pakistan in 1988.

Development Strategies of India
Some of the prominent strategies of India are discussed below
1. Sound Trade System
India was a country which had the history of closed trade. Because of this historical background; there is a critical challenge for India in order to make a new policy which can support the new open trade system. This new reform in economies of India has been introduced and accelerates the economic growth of India.
2. Reduction in Poverty
India has adopted several poverty alleviation programmes to reduce poverty in India. -This would help in increasing per capita income, rise in nutrition level of poors and there is a subsequent fall in percentage of absolute poor in some states.
3. Rural Development
Under this strategy, India adopted various measures for the development of areas that are lagging behind in the overall development of village economy.
4. Employment Generation
Several economic reforms were initiated to generate employment in the country and their aim is to provide gainful self-employment and skilled wage employment opportunities.

Development Strategies of China

After the establishment of People’s Republic of China under one party rule, all the critical sectors of the economy, enterprises and lands owned and operated by individuals were brought under government control.

Certain development strategies of China are discussed below

1. Great Leap Forward (GLF)

This campaign initiated in 1958 aimed at industrialising the country on a massive scale. People were encouraged to set up industries in their backyards. In rural areas, communes were started. Under the commune system, people collectively cultivated lands.

2. Great Proletarian Cultural Revolution (1966-76)

In 1965, Mao Tse Tung started a cultural revolution on a large scale. In this revolution, students and professionals were sent to work and learn from the country side. Unlike GLF, the cultural revolution did not have an explicit economic rationale.

3. 1978 Reforms

Since 1978, China began to introduce many reforms in phases. The reforms were initiated in agriculture, foreign trade and investment sector. In agriculture, lands were divided into small plots which were allocated to individual households. They were allowed to keep all income from the land after paying taxes.

In later phase, reforms were initiated in industrial sector. All enterprises which were owned and operated by local collectives in particular, were allowed to produce goods.

At this stage, enterprises owned by government (known as State Board Enterprises – SOEs), in India we call them public sector enterprises were made to face competition. In reform, prices were fixed in two ways, i.e., farmers and industrial units were required to buy and sell fixed quantities of inputs and outputs on the basis of prices fixed by the government and the rest were purchased and sold at market prices.

Over the years, as production increased, the proportion of goods or inputs transacted in the market also increased. The goal of Chinese economic reforms was to generate sufficient surplus to finance the modernisation of the mainland Chinese economy. In order to attract foreign investors, Special Economic Zones (SEZs) were set up.

Development Strategies of Pakistan
The development strategies of Pakistan are summarised below
1- Mixed Economy
Pakistan follows a mixed economy system where both public and private sectors co-existed.
2. Import Substitution
Pakistan adopted a regulatory policy framework in the late 1950s and 1960s for import industrialisation. The -policy combined tariff protection for manufacturing of consumer goods together with direct import controls on competing imports.
3. Green Revolution
This was introduced to increase the productivity and self sufficiency in food. This increased the output* of food grains. This had changed the agrarian structure dramatically. In 1970’s nationalisation of capital goods took place. Pakistan shifted its policy orientation in 1970’s and 1980’s when private sector got encouragement.
During this period, Pakistan received financial support from Western. This helped the country in stimulating economic growth. Government also offered incentives to private sector. This had a created climate for new investments. And in 1988 certain reforms were also initiated in the country.

DEVELOPMENT STRATEGIES — ANAPPRAISAL

It is common to find developmental strategies of a country as a model to others for lessons and guidance for their own development. It is particularly evident after the introduction of the reform process indifferent parts of the world. In order to learn from economic performance of our neighbouring countries, it is necessary to have an understanding of the roots of their successes and failures. It is also necessary to distinguish between, and contrast, the different phases of their strategies. Though different countries go through their development phases differently, let us take the initiation of reforms as a point of reference. We know that reforms were initiated in China in1978, Pakistan in 1988 and India in1991. Let us briefly assess their achievements and failures in pre and post reform periods.

Why did China introduce structural reforms in 1978? China did not have any compulsion to introduce reforms as dictated by the World Bank and International Monetary Fund to India and Pakistan. The new leadership at that time in China was not happy with the slow pace of growth and lack of modernisation in the Chinese economy under the Maoist rule. They felt that Maoist vision of economic development based on deentralisation, self sufficiency and shunning of foreign technology, goods and capital had failed. Despite extensive land reforms, collectivization, the Great Leap Forward and other initiatives, the per capita grain out put in 1978 was the same as it was in themid-1950s.

It was found that establishment of infrastructure in the areas of education and health, land reforms, long existence of decent ralised planning and existence of small enterprises had helped positively in improving the social and income indicators in the post reform period. Before the introduction of reforms, there had already been massive extension of basic health services in rural areas. Through the commune system, there was more equitable distribution of food grains. Experts also point out that each reform measure was first implemented at a smaller level and then extended on a massive scale. The experimentation under decent ralised government enabled to assess the economic, social and political costs of success or failure. For instance, when reforms were made in agriculture, as pointed out earlier by handing over plots of land to individuals for cultivation, it brought prosperity to a vast number of poor people. It created conditions for the subsequent phenomenal growth in rural industries and built up a strong support base for more reforms.

Scholars quote many such examples on how reform measures led to rapid growth in China. Scholars argue that in Pakistan the reform process led to worsening of all the economic indicators. We have seen in an earlier section that compared to 1980s, the growth rate of GDP and its sector all constituents have fallen in the 1990s.

Though the data on international poverty line for Pakistan is quite healthy, scholars using the official data of Pakistan indicate rising poverty there. The proportion of poor in 1960s was more than 40 per cent which declined to 25 per cent in 1980sand started rising again in 1990s. The reasons for the slow-down of growth and re-emergence of poverty in Pakistan’s economy, as scholars put it, are

(i) agricultural growth and foods supply situation were based not on an institutionalised process of technical change but on good harvest. When there was a good harvest, the economy was in good condition, when it was not, the economic indicators showed stagnation or negative trends

(ii) you will recall that India had to borrow from the IMF and World Bank to set right its balance of payments crisis; foreign exchange is an essential component for any country and it is important to know how it can be earned. If a country is able to build up its foreign exchange earnings by sustainable export of manufactured goods, it need not worry. In Pakistan most foreign exchange earnings came from remittances from Pakistani workers in the Middle-east and the exports of highly volatile agricultural products; there was also growing dependence on foreign loans on the one hand and increasing difficulty in paying back the loans on the other.

However, as stated in the ‘One Year Performance of the (Pakistan)Government’ for the year August2004–2005, the Pakistan economy has been witnessing GDP growth at about8 per cent for three consecutive years(2002–2005). All the three sectors, agriculture, manufacturing and service, have contributed to this trend. Besides facing high rates of inflate on and rapid private station, the government tis increasing the expenditure on various areas that can reduce poverty.

CONCLUSION

What are we learning from the developmental experiences of our neighbours ? India, China and Pakistan have travelled more than five decades of developmental path with varied results. Till the late 1970s, all of them were maintaining the same level of low development. The last three decades have taken these countries to different levels. India, with democratic institutions, performed moderately, but a majority of its people still depend on agriculture. Infrastructure is lacking in many parts of the country. It is yet to raise the level of living of more than one-fourth of its population that lives below the poverty line. Scholars are of the opinion that political instability ,over-dependence on remittances and foreign aid along with volatile performance of agriculture sector are the reasons for the slowdown of the Pakistan economy. Yet, in the recent past, it is hoping to improve the situation by maintaining high rates of GDP growth. It is also a great challenge for Pakistan to recover from the devastating earthquake in 2005,which took the lives of nearly 75,000people and also resulted in enormous loss to property. In China, the lack of political freedom and its implications for human rights are major concerns; yet, in the last three decades, it used the ‘market system without losing political commitment’ and succeeded in raising the level of growth along with alleviation of poverty. You will also notice that unlike India and Pakistan ,which are attempting to privatize their public sector enterprises, China has used the market mechanism to ‘create additional social and economic opportunities’. By retaining collective ownership of land and allowing individuals to cultivate lands, China has ensured social security in rural areas. Public intervention in providing social infrastructure even prior to reforms has brought about positive results in human development indicators in China.

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Rocks

2018-04-02T00:00:00.005-07:00

Rocks

Making up the majority of the Earth's crust, rock is usually defined as a mixture of common minerals. Rocks can be hard or soft, as small as a grain or as large as a building. They have been an integral part of the history of mankind, first being used as tools for hunting and defense, and as a building materials to construct shelters and monuments. Combined with the effects of tectonics, weathering and vegetation, rocks define the natural landscapes we see around us. The minerals and metals we find in rocks are essential to the prosperity and cultural splendor of human civilization. There are many kinds of rock, and they can be classified in a number of ways. However, geologists classify rocks based on how the rocks were formed. The three classes are igneous rocks (formed directly from liquid rock), metamorphic rocks (formed by direct alteration of existing rocks), and sedimentary rocks (formed by eroded materials from other rocks).

Sedimentary rocks

Formation of sedimentary rocks

A river carries, or transports, pieces of broken rock as it flows along. When the river reaches a lake or the sea, its load of transported rocks settles to the bottom. We say that the rocks are deposited. The deposited rocks build up in layers, called sediments. This process is called sedimentation.

The weight of the sediments on top squashes the sediments at the bottom. This is called compaction. The water is squeezed out from between the pieces of rock and crystals of different salts form.

The crystals form a sort of glue that sticks or cements the pieces of rock together. This process is called cementation.

These processes eventually make a type of rock called sedimentary rock. It may take millions of years for sedimentary rocks to form.

These are the different processes in order:

sedimentation → compaction → cementation

Igneous rocks

The second type of rock we'll look at is igneous rock.

Formation

The inside of the Earth is very hot - hot enough to melt rocks. Molten (liquid) rock forms when rocks melt. The molten rock is called magma. When the magma cools and solidifies, a type of rock called igneous rock forms.

What are they like?

Igneous rocks contain randomly arranged interlocking crystals. The size of the crystals depends on how quickly the molten magma solidified. The more slowly the magma cools, the bigger the crystals.

You may have done an experiment at school with a substance called salol. If molten salol cools slowly, you get big crystals. If it cools quickly, you get small crystals.

Obsidian and basalt

If the magma cools quickly, small crystals form in the rock. This can happen if the magma erupts from a volcano. Obsidian and basalt are examples of this type of rock. They are called extrusive igneous rocks because they form from eruptions of magma.

Granite and gabbro

If the magma cools slowly, large crystals form in the rock. This can happen if the magma cools deep underground. Granite and gabbro are examples of this type of rock. They are intrusive igneous rocks because they form from magma underground.

Unlike sedimentary rocks, igneous rocks do not contain any fossils. This is because any fossils in the original rock will have melted when the magma formed.

Metamorphic rocks

Metamorphic rocks are the third type we'll look at. They formed from other rocks that are changed because of heat or pressure.

Formation

Earth movements can cause rocks to be deeply buried or squeezed. As a result, the rocks are heated and put under great pressure. They do not melt, but the minerals they contain are changed chemically, forming metamorphic rocks.

Sometimes, metamorphic rocks are formed when rocks are close to some molten magma, and so get heated up.

Remember that metamorphic rocks are not made from melting rock. (Rocks that do melt form igneous rocks instead.)

What are metamorphic rocks like?

When a metamorphic rock is formed under pressure, its crystals become arranged in layers. Slate, which is formed from shale, is like this. Slate is useful for making roof tiles because its layers can be split into separate flat sheets.

Marble is another example of a metamorphic rock. It is formed from limestone.

Metamorphic rocks sometimes contain fossils if they were formed from a sedimentary rock, but the fossils are usually squashed out of shape.

Metamorphic rocks can be formed from any other type of rock - sedimentary or igneous. Remember these two examples of common metamorhpic rocks and where they come from:

slate is formed from shale
marble is formed from limestone

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MACROECONOMICS

2018-04-01T01:03:00.004-07:00

MACROECONOMICS

Introduction to Macro Economics, it is essential that you, yourself develop an understanding of what Macroeconomics is and how it is different from Microeconomics. You must have noticed that these terms are invariably used by all; but as Economics Teacher you must have a deeper insight about what these terms connote and make students understand in simpler words how Macroeconomics is different from Microeconomics and also how both are important for understanding Individual Behaviour and Aggregated Indicators i.e. GDP, Unemployment Rate, Price Indices etc. Macroeconomics Microeconomics is derived from Greek Prefix "macr(o)" meaning "large" + economics) is a branch of economics dealing with the performance, structure, behavior, and decision making of the entire economy. This includes a national, regional, or global economy. Microeconomics and Macroeconomics are two most general fields in Economics.

What is the difference between Microeconomics and Macroeconomics?

Microeconomics is primarily focused on the Individual Agents i.e. Firms and Consumers and how their behaviors determine Price and Quantities in specific markets.

Macroeconomics is a broad field of study. It studies Aggregated Indicators such as GDP, Unemployment Rates, and Price Indices to understand how the whole economy functions. Macroeconomists develop models that explain relationship between factors such as National Income, Output, Consumption, Unemployment, Inflation, Saving, Investment, International Trade and International Finance.

Macroeconomics models and their forecasts are used by both Governments and large corporations to assist in the development and evaluation of economic policy and business strategies.

Fiscal Policy and Monetary Policies are good examples of how economic management is achieved through these government strategies.

It is also vital to point out here that to avoid major Economic Shocks, such as Great Depression, Recession, Melt down etc., Government makes adjustments through policy changes, they hope, will stabilize the economy.

Same Basic Concepts

Computation of National Income is important as it reflects the leveled growth & development of any country. But before you introduce children with the concept, meaning and definition of National Income/GDP and other related terms, introduce and explain the basic concepts/terms which will invariably be used in the computation of National Income. These concepts are explained briefly as under:

Consumption Goods

Consumption refers to the act or a process to consume which means using up of goods and services by consumers for satisfaction of their wants. Consumption good or service is that which is used (without further transformation in production) by Households or Government units for the direct satisfaction of individual needs or wants or the collective needs of members of community. It can also be defined as any commodities that are used by the household for their personal use. Consumer goods are final goods specifically intended for mass market. These goods do not include investment, for example Bread, butter, milk, tea, coffee, etc. which are directly used by consumers for satisfaction of their needs. These are example of One Time Consumption goods (also known as single use consumer goods) but there can be examples like machine, furniture, readymade clothes which are repeatedly used but they are used directly and hence fall in the category of Durable Consumption Goods. Hence consumer goods are the end result of the production.

Capital Goods

Goods that are used in producing other goods, rather than being bought by consumers directly for satisfaction of their needs are called Capital Goods. These are tangible Explain to students that final goods may be divided in to two categories i.e. Consumer goods & Producers goods. Assets of an organization which are used to produce goods and services are called Capital goods. These goods include items such as Buildings, Equipments, and Machinery etc. Capital goods are not used up by producer in a single year of production. These exist for many years and are repeatedly used over a period of time. Capital goods may undergo capital improvement which typically extend their life and increases their productivity. These are also known as producer's goods as they are being used to create other goods.

Final Goods

Final goods are goods that are ultimately consumed rather than used in the production of other goods. It refers to finished goods which are sold in the market for consumption & investment purpose. These goods satisfy the wants of ultimate producers or consumers or both. Buying of furniture by a household consumer for his house is final good for him whereas the same when bought by a producer for his office is producer’s final goods. Another example can be flour used by the household are final good whereas the same flour used by the baker is a producer's goods.

Intermediate Goods

All those goods which are used by the producers for producing other goods are known as Intermediate goods.

These goods are used as inputs in the production of other goods such as partially finished goods. These goods are demanded for producing other goods. Thus intermediate goods are those goods which are sold by one industry to another either for resale or for producing other goods. Stocks of Raw Materials and Semi finished goods fall under the category of intermediate goods. Another example can be of raw cotton used for the production of yarn is an Intermediate good and when the same yarn is sold to the owner of the textile mill for the production of cloth then the same yarn becomes intermediate good for the owner.

Stocks & Flows

Stocks & Flows have natural meaning in many contexts outside of business and its related fields. Let us define/give meaning to both the terms 'Stock' & 'Flow' and then show the relatedness of the two and how these are impacting on an economy/business.

Stock

A 'Stock' refers to the value of goods & services at a particular point of time. It is an entity that is accumulated over by inflows and/or depleted by outflows. Therefore, we can say that the 'stock' can only be changed by a 'flow'.

'Stocks' typically have a certain value of each moment of time, for example the size of population at a certain moment. i.e.

As per census 2001, the population of India stood at 102 billion, whereas according to 1991 census the population of India 'stood at 84.6 billion. The change/Increase in the figure at two census i.e. 1991 & 2001 is because of the additional population (flow) in 10 years.

Flow

It is change in stock over period of time. Change refers to inflows (adding to the stock) and outflows (subtracting from the stock). Flows typically are measured over a certain interval of time. For example the increase in population census 1991 to census 2001 is due to increase in number of births in a period of 10 Years. To conclude we may say that 'Stock' is a Static concept whereas 'Flows' represents Dynamic concept.

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How to find a square root

2018-03-30T23:10:00.000-07:00

How to find a square root

Finding the square root of a number is the inverse operation of squaring that number. Remember, the square of a number is that number times itself.

Square of n = n²

Square of 2 = 2*2 = 2² = 4

The perfect squares are the squares of the whole numbers.

Perfect squares :

1,4,9,16,25,36,49,64,81,100

What is the number you want to find the square root of? Here's one we'll use:

46656

First, divide the number to be square-rooted into pairs of digits, starting at the decimal point. That is, no digit pair should straddle a decimal point. (For example, split 1225 into "12 25" rather than "1 22 5"; 6.5536 into "6. 55 36" rather than"6.5 53 6".)

Then you can put some lines over each digit pair, and a bar to the left, somewhat as in long division.

+--- ---- ----

| 4 66 56

Find the largest number whose square is less than or equal to the leading digit pair. In this case, the leading digit pair is 4; the largest number whose square is less than or equal to 4 is 2.

Put that number on the left side, and above the first digit pair.

+--- ---- ----

2 | 4 66 56

Now square that number, and subtract from the leading digit pair.

+--- ---- ----

2 | 4 66 56

|-4

+----

Extend the left bracket; multiply the last (and only) digit of the left-hand number by 2, put it to the left of the difference you just calculated, and leave an empty decimal place next to it.

+--- ---- ----

2 | 4 66 56

|-4

+----

4_ | 0

Then bring down the next digit pair and put it to the right of the difference.

+--- ---- ----

2 | 4 66 56

|-4

+----

4_ | 0 66

Find the largest number to put in this blank decimal place such that that number, times the number already there plus the decimal place, will be less than the current difference. For example, see if 1 * 41 is ≤ 66, then 2*42 ≤ 66, etc. In this case it's a 1. Put this number in the blank you left, and in the next decimal place on the result row on the top.

2 1

+--- ---- ----

2 | 4 66 56

|-4

+----

41 | 0 66

Now subtract the product you just found.

2 1

+--- ---- ----

2 | 4 66 56

|-4

+----

41 | 0 66

|- 41

+--------

Now, repeat as before: Take the number in the left column (here, 41) and double its last digit (giving you 42). Copy this below in the left column, and leave a blank space next to it. (Double the last digit with carry: for example, if you had not 41 but 49, which is 40+9, you should copy down 40+18 which is 58.) Also, bring down the next digit pair on the right.

2 1

+--- ---- ----

2 | 4 66 56

|-4

+----

41 | 0 66

|- 41

+--------

42_ 25 56

Now, find the largest digit (call it #) such that 42# * # ≤ 2556. Here, it turns out that 426 * 6 = 2556 exactly.

2 1 6

+--- ---- ----

2 | 4 66 56

|-4

+----

41 | 0 66

|- 41

+--------

426 | 25 56

|- 25 56

+-------------

When the difference is zero, you have an exact square root and you're done. Otherwise, you can keep finding more decimal places for as long as you want.

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Nationalism in India

2018-03-29T23:40:00.001-07:00

Nationalism in India

The First World War, Khilafat And Non-Cooperation

Effects of First World War: The War led to a huge increase in defence expenditure. This was financed by war loans and by increasing taxes. Customs duties were raised and income tax was introduced to raise extra revenue. Prices of items increased during the war years. The prices doubled between 1913 and 1918. The common people were the worst sufferers because of price rise. Forced recruitment of rural people in the army was another cause of widespread anger among people.

Crop failure in many parts of India resulted in acute shortage of food. Influenza epidemic further aggravated the problem. According to 1921 census, about 12 to 13 million people died because of famines and epidemic.

The Idea of Satyagraha

Mahatma Gandhi advocated a novel method of mass agitation; called satyagraha. This method was based on the idea that if someone is fighting for a true cause, there is no need to take recourse to physical force to fight the oppressor. Gandhi ji believed that a satyagrahi could win a battle through non-violence, i.e. without being aggressive or revengeful.

Some early satyagraha movements organized by Gandhi:

a. Peasants’ movement in Champaran in 1916.

b. Peasants’ movement in Kheda in 1917.

c. Mill workers’ movement in Ahmadabad in 1918.

The Rowlatt Act(1919):

The Rowlatt Act was passed by the Imperial Legislative Council in 1919. The Indian members did not support the Act, but it was passed; nevertheless. The Act gave enormous powers to the government to repress political activities. It allowed detention of political prisoners without trial for two years.

On 6th April, 1919; Gandhiji launched a nationwide satyagraha against the proposed Rowlatt Act. The call of strike on 6th April got huge response. People came out in support in various cities, shops were shut down and workers in railway workshops went on strike. The British administration decided to clamp down on the nationalists. Several local leaders were arrested. Mahatma Gandhi was barred from entering Delhi.

Jallianwalla Bagh

On 10th April 1919; in Amritsar; the police fired upon a peaceful procession. This provoked widespread attacks on government establishments. Martial law was imposed in Amritsar and the command of the area was given to General Dyer.

The infamous Jallianwalla Bagh massacre took place on 13th April; the day on which Baisakhi is celebrated in Punjab. A crowd of villagers came to participate in a fair in Jallianwalla Bagh. This was enclosed from all sides with narrow entry points. General Dyer blocked the exit points and opened fire on the crowd. Hundreds of people were killed in the incident. Public reaction to the incident took a violent turn in many north Indian towns. The government was quite brutal in its response. Things took highly violent turn. Mahatma Gandhi called off the movement as did not want violence to continue.

Need of Wider Spread of Movement: The Rowlatt satyagraha was limited mainly to the cities and towns. Mahatma Gandhi felt the need of a more broad-based movement in India. He was convinced that it could be only possible by bringing the Hindus and Muslims on a common platform.

Khilafat Movement

The Khilafat issue gave him the opportunity to bring the Hindus and Muslims on a common platform. The Ottoman Turkey was badly defeated in the First World War. There were rumours about a harsh peace treating likely to be imposed on the Ottoman emperor; who was the spiritual head of the Islamic world (the Khalifa). A Khilafat committed was formed in Bombay in March 1919 to defend the Khalifa. This committee had leaders like the brothers Muhammad Ali and Shaukat Ali. They also wanted Mahatma Gandhi to take up the cause to build a united mass action. At the Calcutta session of the Congress in September 1920, the resolution was passed to launch a non-cooperation movement in support of Khilafat and also for swaraj.

Non-Cooperation Movement

In his famous book Hind Swaraj (1909) Mahatma Gandhi declared that British rule was established in India with the cooperation of Indians, and had survived only because of this cooperation. If Indians refused to cooperate, British rule in India would collapse within a year, and swaraj would come. Gandhiji believed that if Indians begin to refuse to cooperate, the British rulers will have no other way than to leave India.

Some of the proposals of non-cooperation movement:

Surrender the titles which were awarded by the British government.
Boycott civil services, army, police, courts, legislative councils and schools.
Boycott foreign goods.
Launch full civil disobedience campaign, if the government persisted with repressive measures.

Differing Strands within the Movement: The Non-Cooperation-Khilafat Movement began in January 1921. Various social groups participated in this movement, each with its own specific aspiration. All of them responded to the call of Swaraj, but the term meant different things to different people.

The Movement in the Towns:

The movement started with good participation from the middle-class in the cities.
Thousands of students left government-controlled schools and colleges, headmasters and teachers resigned, and lawyers gave up their legal practices.
The council elections were boycotted in most provinces except Madras. In Madras, the Justice Party, the party of the non-Brahmans, felt that entering the council was one way of gaining some power – something that usually only Brahmans had access to.
Foreign goods were boycotted, liquor shops picketed, and foreign cloth burnt in huge bonfires. The import of foreign cloth halved between 1921 and 1922, its value dropping from Rs 102 crore to Rs 57 crore. The boycott of foreign cloths helped in increasing the demand of cloths made in India.

Reasons for Slowdown of Movement:

Khadi was more expensive than mill-made cloth. The poor people could not afford to buy khadi.
Boycott of British institutions posed a problem of lack of alternative Indian institutions. Such institutions were slow to come up. Students and teachers began coming back schools. Similarly, lawyers resumed their work in the courts.

Rebellion in the Countryside: From the cities, the Non-Cooperation Movement spread to the countryside. It drew into its fold the struggles of peasants and tribals which were developing in different parts of India in the years after the war.

Awadh

The peasants’ movement in Awadh was led by Baba Ramchandra. He was a sanyasi who had earlier worked in Fiji as an indentured labourer. The peasants were against the high rents and may other cess which were demanded by talukdars and landlords. The peasants demanded reduction of revenue, abolition of begar, and social boycott of oppressive landlords.

Jawaharlal Nehru began touring the villages in June 1920. He tried to understand the problems of the peasants. Oudh Kisan Sabha was set up by October. It was headed by Jawaharlal Nehru, Baba Ramchandra and a few others. By associating itself with the peasants’ movement, Congress was able to integrate the movement in Awadh with a wider non-cooperation movement. At many places, people stopped paying rents by invoking the name of the Mahatma.

Tribal Peasants

Tribal peasants gave their own interpretation of Mahatma Gandhi and the idea of swaraj. The tribals were prevented from entering the forests to graze cattle, or to collect fruits and firewood. The new forest laws were a threat to their livelihood. The government forced them to do begar on road construction.

Many rebels from the tribal areas became non-violent and often carried guerilla warfare against the British officials.

Swaraj in the Plantations

The plantation workers were not permitted to leave the tea gardens without permission; as per the Indian Emigration Act of 1859. When the news of Non-Cooperation Movement spread to the plantations, many workers began to defy the authorities. They left plantations and headed towards their homes. But they got stranded on the way because of a railway and steamer strike. They were caught by the police and brutally beaten up.

Many analysts are of the opinion that the vision of the movement was not properly defined by the Congress. Different people interpreted the term ‘swaraj’ in their own ways. For them, swaraj meant an end to all their problems. However, people from various strata of society began to chant the name of Gandhi and the slogan of Swatantra Bharat. In some way or the other, they were trying to relate to the wider movement which was beyond their comprehension.

If you have any doubt to related this topic comment below :

You can suggest any other topic in history which you want to know more

Real Numbers

2018-03-29T00:01:00.002-07:00

Real Numbers

Numbers

There are two types of Numbers.

1. Real Numbers

2. Complex Numbers (Real numbers + Imaginary Numbers)

Real Numbers: The numbers which can be represented on the number line by a unique point are called real numbers.

Examples: -1, -2, -3, -4 ....................... , and 1, 2, 3, 4, 5.........................

Complex Numbers: Complex numbers are the numbers which consist of both real and Imaginary numbers.

Examples: 2 + i√3, where 2 is real part and i√3 is imaginary part.

Real Numbers

(A) Rational Numbers: The numbers which can be express in the form of p/q, and q≠0 such a numbers are known as real numbers.

(B) Irrational Numbers: The numbers which are not rational numbers but these an be represented on a number line, such numbers are known as irrational numbers.

Rational Numbers

(I) Integers:

(a) Whole numbers: These are the set of positive integers from 0. Which have not decimal and fractional part. Such numbers are known as whole numbers.

Example: 0, 1, 2, 3, 4, 5, ...........................

(i) Natural Numbers: Natural numbers counting begin from 1 to ∞ (infinity). such numbers are called natural numbers.

Ex: 1, 2, 3, 4, 5 ....................................... ∞.

(ii) Zero: 0

(b) Negative integers: The numbers before 0 on number line is called as negative integers these are -1, -2, -3, -4 ............................. -∞.

(II) Fractional Numbers:

(a) Proper fraction

(b) Improper fraction

Natural numbers

(a) Odd Numbers: The numbers which can not be divided by 2 are called odd numbers.

Example: 1, 3, 5, 7, 9, 11, 13, 15 ................................................. ∞.

(b) Even Numbers: The numbers which can be divided by 2 are called even numbers.

Example: 2, 4, 6, 8, 10, 12, 14, 16 ................................................ ∞.

(d) Composite Numbers:

(e) Co-prime Numbers:

(f) Perfect Numbers:

Properties of real numbers

Commutative property- If we have real numbers m,n. The general form will be m + n = n + m for adaddition and m.n = n.m for multiplication.

Associative property- If we have real numbers m, n, r. The general form will be m + (n + r) = (m + n) + r for addition(mn) r = m (nr) for multiplication

Distributive property- If we have real numbers m,n,r. The general form will be – m (n + r) = mn + mr and (m + n) r = mr + nr

Identity property- For addition: m + (- m) = 0

Euclid’s Division Lemma

For a and b any two positive integer, we can always find unique integer q and r such that
a=bq + r , 0 ≤ r < b

It is basic concept and it is restatement of division

a is called dividend
b is called divisor
q is called quotient
r is called remainder.

If r =0, then b is divisor of a.

Proof of Euclid's Division Lemma

Here we need to argue that q and r are no unique
Let us assume q and r are not unique i.e. let there exists another pair q₀ and r₀ i.e. a = bq₀ + r₀, where 0 ≤ r₀ < b

=> bq + r = bq₀ + r₀
=> b(q - q₀) = r - r₀ ................ (I)

Since 0 ≤ r < b and 0 ≤ r₀ < b, thus 0 ≤ r - r₀ < b ......... (II)

The above eq (I) tells that b divides (r - r₀) and (r - r₀) is an integer less than b. This means (r - r₀) must be 0.
=> r - r₀ = 0
=> r = r₀

Eq (I) will be, b(q - q₀) = 0
Since b > 0, => (q - q₀) = 0
=> q = q₀

Since r = r0 and q = q₀, Therefore q and r are unique.

HCF (Highest common factor)

Before starting on this topic, we need to prove a important theorem m which will be used in finding HCF between two numbers

Theorem

If a and b are positive integers such that a = bq + r, then every common divisor of a and b is a common divisor of b and r, and vice-versa.

Proof : Let m be a common divisor of a and b. Then,
m| a => a = mx for some integer x
m| b => b = mq2 for some integer y
Now, a = bq + r
=> r = a - bq
=> r = mx - my q
=> r = m( x - yq)
=> m| r
=> m| r and m | b
=> m is a common divisor of b and r.
Hence, a common divisor of a and b is a common divisor of b and r

How to find HCF (Highest common factor)

Now HCF of two positive integers can be find using the Euclid's Division Lemma algorithm and above stated theorem

We know that for any two integers a,b. we can write following expression
a=bq + r , 0 ≤ r < b
If r=0 ,then
HCF( a,b) =b
If r >0 , then
HCF ( a,b) = HCF ( b,r) as already proved from above theorem

Again expressing the integer b,r in Euclid's Division Lemma, we get
b=pr + r1
HCF ( b,r)=HCF ( r,r1)
Similarly successive Euclid 's division can be written until we get the remainder zero, the divisor at that point is called the HCF of the a and b.

If You Still have any doubt, feel free to comment!

Bio-Molecules

2018-03-27T22:44:00.000-07:00

Bio-Molecules

Living cells are composed of both organic and inorganic components.

How to analyse chemical composition:

For organic compounds:

·         Living tissue + trichloro acetic acid and grind it to form slurry.

·         Filter the slurry to obtain 2 fractions like Filtrate/ acid soluble and Retentate/ acid insoluble

For inorganic compounds:

Sample of tissue should be burnt to obtain ash and different kinds of inorganic compounds were identified.

Types of biomolecules - Micro molecules and Macro molecules

·         Micro molecules are known as monomers

·         Macromolecules are known as polymers

Primary and Secondary metabolites: These are biomolecules in living cells metabolites.

Primary metabolites: are those which have identifiable functions and play specific roles in normal physiological processes. Eg. Amino acids, nitrogenous bases, proteins and nucleic acid.

Secondary metabolites :are product of certain metabolic pathways from primary metabolites.

·         Pigments – anthocyanin, carotenoids

·         Drugs – vinblastin, curcumin

·         Alkaloids - morphine, codeine

·         Essential oils – lemon grass oil

·         Polymeric compounds - rubber gum, cellulose, resins

Biomacromolecules

It is molecules with weight greater than 1000 dalton found in acid insoluble fraction.

Eg- polysaccharides, nucleic acid, proteins and lipids.

Polysaccharides :

·         Long chain of polymers of monosaccharides – 2 types of Mono-polysaccharides (cellulose, starch – made of only Glucose monomers).

·         Heteropolymer – chitin

·         Inulin -is a polymer of fructose

·         Glycogen – polymer of glucose in animal tissues

·         Monosaccharides are joined by Glycosidic acid bond, right end is reducing and left end is non reducing.

·         Starch forms helical secondary structures. Starch can hold Iodine molecules in helical portion and form blue colour. But Cellulose does not contain complex helices and cannot hold iodine.

·         Complex polysaccharide: .Plant cell wall (cellulose ), Paper (plant pulp ), Cotton, Fibre (cellulose) Exoskeleton of animals, building blocks, amino-sugars and chemically modified Sugars like, Eg. – Giucosamine (N – acetyl galactosamine).

Nucleic acids:

·         DNA – Polynucleotide chain, double stranded (deoxy ribose sugar) – nitrogenous bases are A, G, C and T

·         RNA – single stranded Polymer of ribo-nucleotides (ribose sugar) – A, G, C and U

·         Nucleotides – nitrogenous base + pentose sugar + phosphate group

·         Nucleoside – nitrogenous base + pentose sugar

·         Nitrogenous bases

1.       Adenine (A)

2.       Guanine(G)

3.       Cytosine( C )

4.       Thymine (T)

Phospho-diester bonds – covalent bond formed between nucleotides.

Proteins:

      Polymer of amino acids (peptide bonds)

1.       Primary structure – linear chain of aminoacids linked by peptide bonds – non functional.

2.       Secondary structure – alpha-helix or beta-pleated structure with peptide and hydrogen bonds.

3.       Tertiary structure – long chain of coiled structure with peptide, hydrogen, disulphide and ionic bonds – functional structurte of protein.

4.       Quaternary structure – group of more than two tertiary structured proteins (eg- haemoglobin – made of two alpha and two beta chains).

Nature of bonds linking monomers in a polymer:

1.       Amino acids are linked by Peptide bonds

2.       Monosaccharides are linked by Glycosidic bond

3.       Nucleotides are linked by Phosphodiester bond between 3-C of one nucleotide with

5-C of another - Each helix of DNA contains 10 base pairs with the length of 3.4 nm (34 Ao).

Concept of Metabolism:

·         Biomolecules have turn over (because constantly changing from one form to another)

·         Chemical reactions are called metabolism.

Examples:

·         Amino acids can be formed by the removal of amino group in a nucleotide base.

·         Hydrolysis of disaccharides – 2 monosacharides

·         Linked chemical reactions are called Metabolic pathways, it is a catalysed reaction by enzymes.

Metabolic pathways in living system:

·         Anabolic pathways - making / constructing big molecules from micromolecules (eg – photosynthesis)

·         Catabolic pathways – breaking down of big molecules in to smaller ones (eg – respiration)

·         For both ATP is required (energy currency)

The living state

·         Blood glucose – should be 4.5 -5.0mM

·         Hormones – in nanograms/mL

·         System at equilibrium cannot perform work

·         As living organisms work constantly, it is non equilibrium.

·         Hence the living state is non equilibrium steady state to be able to perform work.

Enzymes Vs Catalysts:

·         Enzyme – helps in chemical reactions

·         Inorganic reaction :- Ba(OH)2 + H2SO4 --> BaSO4 + 2 H2O – No enzyme used.

·         Organic reaction - Enzyme used

·         Carbonic anhydrase – fastest enzyme - without enzyme 200 molecules / hr - with enzyme 600,000 molecules / sec.

·         Activation energy is the energy needed to do work.

Nature of enzyme action:

Enzyme + Substrate --> ES complex --> Enzyme + Product

ENZYME

CATALYST

1. It is produced by living cells and made of protein.

   It is chemical substances and help in chemical reactions.

2. It can work well at optimum temperature of 40o C.

   It can work even at 80 – 90o C.

3. It reduces the activation energy.

   It requires different level of energy.

Properties of Enzymes:

1.       All enzymes are proteins, but all proteins are not enzymes.

2.       Enzymes are specific with their substrates as their active sites are different for different substrates.

3.       Enzymes are of 2 types 1. Builders. 2. Breakers

4.       Enzyme does not get used up during the reaction, as it does not change its shape – hence less enzymes are required.

Denaturation:

The enzyme changes its shape and the substrate cannot bind with the enzyme - affect tertiary structure of the protein.

Factors affecting enzyme activity:

·         Effect of temperature: temperature at which the enzyme gives its maximum rate of reaction is known as optimum temperature (40o C).

·         Effect of pH - different enzymes work at different pH, for example, enzyme pepsin works at pH 2, and enzyme amylase at pH 7, it is called optimum pH.

·         Substrate concentration -

Enzyme inhibition – enzyme action can be inhibited by other chemical molecules called inhibitors.

Competitive inhibition: Inhibitor chemical molecule resembles the structure of substrate and bind with

                                          the active site of enzyme instead of substrate, hence there is no production of

                                          products.

Eg. Inhibition of Succinic dehydrogenase by Malonate (inhibitor), which resembles the

       substrate Succinate in structure.

·         All enzymes are proteins but all proteins are not enzymes. Eg. Heamoglobin is a protein but not an enzyme.

·         Enzymes at low temperature become inactive, enzymes at high temperature denatures.

Classification and nomenclature of enzymes: Based on type of reaction they classified into 6 classes.

1.       Dehydrogenases/ oxidoreductases -

S reduced + S’ oxidized ------ S oxidized + S’ reduced

2.       Transferases -

S-G + S’------- S+S’-G

3.       Hydrolases -

Hydrolysis of ester ether, peptide and glycoside

C –C , C- halides , P-N bonds

4.       Lyases -

Removal of group from substrates other than hydrolysis ( from double bond )

X Y

l   l

C C ------ X-Y+C =C

5.       Isomerases - Inter-conversion of optical geometrical or positional isomers.

6.       Ligases – linking two compounds. C-O, C-S, C-N, P-O

Co-factors:

·         It is a non – protein part, makes enzyme more active – protein part is called Apoenzyme.

·         There are 3 kinds of factors:

1.       Prosthetic group - tightly bound with apoenzyme. Eg. Peroxidase, Catalases.

2.       Co-enzyme – bound transient form. Eg. NAD, NADP (Nicotinamide Adenine Dinucleotide Phosphate)

3.       Metal ions - Form coordination bonds. Eg. Fe, Zn.

Friction

2018-03-26T22:44:00.000-07:00

Friction

About
We all know that what would happen if we slide a book kept along a horizontal table .Yes it would first sliding and then finally would come to rest

This force opposing continous motion of book on the table is called force of friction
Whenever surface of one object slides over another ,both the bodies exerts force of friction on each other
Here in this chapter,we will consider frictional forces acting between a pair of surfaces
Frictional force comes into action whenever two surfaces of two bodies comes in contact with each other(Both the bodies could be moving or rest).Both the bodies exert a force on each other which is basically E.M in nature and this force is a contact force
Magnitude of contact forces on two bodies are equal but they are opposite in direction
Contact forces also depend on the nature of the surfaces of the two bodies kept in contact,how both the bodies are moving and all the forces acting on them
Consider a block resting on the horizontal,Now two bodies exert equal and opposite contact force on each other . Let F_c is the contact force both the bodies exert on each other

· Direction of the contact force acting on a body need not necessarily be perpendicular to the surface of contact

· Contact force F_c can be resolved into two components.The component of F_c along the normal to the surface is called Normal
contact force and component parallel to the surface is called friction (f) Friction is subdivided into two catagories namely
1. Static Friction
2. Kinetic Friction
Static friction is experienced betweem the non moving surfaces i.e the bodies at rest and kinetic friction or dynamic friction is experienced between the moving surfaces or between the bodies in motion

Static Friction

· We already know that frictional forces can also act between the bodies in contact with each other even if they are not moving and such type frictional force is known as static friction

· Consider a heavy metal block kept on the floor and you are trying very hard to push it to another location and you are not able to slide it even by a centimeter

_·Since the block is at rest resultant force on it should be zero.To counter balance the force applied by you ,floor exerts a frictional force on the block _s

_·_{Now if you begin to increase the
magnitude of force gradually then bloack does not start moving until force
applied is greater then a minimum value of force}

_·_{This force of static friction
must be overcome by the applied force before the body at rest begin to move}

_·_{Force of friction is always equal
and opposite to the external applied force as long as the body is at rest}

_·_{This means that static friction
force is a self adjusting force.It adjust its value accordingly with the
increase in magnitude of applied force}

· This frictional force cannot be unlimited and its value cannot go beyond a maximum value f_ms

· This maximum value of static friction between the two surfaces in contact is known as limiting friction

· Thus magnitude of static friction can not go beyond the magnitude of the limiting friction i.e, f_s <= f_ms

· This limiting friction is proportional to the normal contact force (N) between the bodies i.e,
f_ms is proportional to N
f_ms=μ_sN

· Where N =Normal contact force
μ_s is the proportionality constant known as coefficent of static friction

· Value of coefficent of static friction depends on the material and roughness of the surfaces of bodies in contact

· f_ms is the maximum value that force of static friction acting between two bodies can reach

· The actual force of static friction can be equal to zero or less then f_ms and its value depends on the force applied on the body thus
f_s <= f_ms=μ_sN

Kinetic or dynamic friction

· We already know that static frictional force exists between two surfaces in contact before there is relative motion between two surfaces

· When applied force becomes greater then limiting friction force,then motion of the body starts and kinetic friction comes into existence

· Thus when bodies in contact moves relative to each other then friction devloped between them is called kinetic or dynamic friction

· Initially the block is at rest,now we push the block on the surface such that it begins to move or start sliding on the surface

· When the block is sliding over the surface each body exerts a frictional force on the other side parallel to the surface in contact

· The force of friction acting on the block B due to surface S is along the direction opposite to the motion of B with respect to S.Thus force of kinectic friction opposes the relative motion between the bodies in motion

· The frictional force acting on the block is along the direction towards the left and an equal force acts on the surface S directed towards the rights

· Thus we can say that sliding friction on a body B against surface S is opposite to the velocity of the body B with respect to S

· Force of kinetic friction is denoted by f_k and its magnitude is always less then the magnitude of limting friction i.e maximum static friction
i.e f_k < f_ms

· kinetic friction force is proportional to the normal contact force between the surfaces i.e
f_k is proportional to N
=> f_k =μ_kN
Where N =Normal contact force
μ_k is the proportionality constant known as coefficent of kinetic friction and its value depends on the nature of the two surfaces in contact

· f_k < f_ms, this inequality shows that force required to start the motion is greater then the force required to maintail the further motion of the body

Rolling Friction

Consider a situation of the ring or a sphere rolling without slipping over a horizontal plane.In this case there is only one point of contact between the body and the plane
The frictional forces developed between two surfaces in case described above is called rolling friction
Rolling friction developes between two surfaces when one body rolls over the surface of another body
We know that it is very difficult to pull a heavy metal box on a rough surface and if we attah four metal wheel to the box it becomes easiar to move the
Thus resistance offered by the surface during rolling is relatively less than offered during sliding friction
This is because while rolling surfaces in contact do not rub each other
Rolling friction is negligible in comparision to the kinetic and static friction which are present simlutanously
In many parts of the machine where this type of friction is undesirable ball bearings(small steel balls) are generally kept between the rotating parts of

Angle of friction

It is the angle which the normal force N makes with the contact force when the equlibrium is limiting i.e when the condition of maximum static friction
Consider a block of mass m resting on a horizontal surface .Weight W=mg of this block is balanced by the normal force (N) of reaction

Mathematically
W=mg=-N
if F is the contact force which each body exerts on the another body then this contact force can be resolved into two components
Perpendicular Components which is normal force N
Components parallel to the contact surface known as friction which is usually denoted by the f_s,f_k or f_ms
Angle BCD respresented by λ is angle of friction
Since N and f_ms are components of the contact force F,so we can write
Fcosλ=N
and Fsinλ=f_ms
or we can say
tanλ=f_ms/N
Also from the defination of static friction we know that
f_ms=μ_sN So tan λ=μ_s
Thus we can conclude that coefficient of static friction is equal to the tangent of the angle of friction

Methods to Reduce Friction;

Friction can be reduced by the numbers of methods.Some of them are listed below:

(a)Lubrication: when a lubricant is applied between the two surfaces in contact then a thin layer of lubricant is formed between the two surfaces resulting in reduction in friction.Example of Lubricant Grease oil, graphite , compressed air

(b)Polishing : Irregularities of a surface can be reduced by polishing the surface smooth which results in reduction in friction
(c) Friction between the two surfaces can be reduced by using ball bearing between the two surfaces.Also sliding friction can be converted into rolling friction which is much less then sliding friction

Metals and Non-Metals (important questions)

2018-03-26T22:03:00.001-07:00

Metals and Non-Metals (important questions)

Q1. Give examples of five elements that are metallic.
Ans. Copper, iron, gold, silver and aluminium.
Q2. Give examples of five elements that are non-metallic.
Ans. Sulphur, phosphorus, carbon, hydrogen, oxygen, chlorine and bromine.
Q3. How do metals and non-metals combine?
Ans. Metals and non-metals combine by transference of electrons from metals to non-metals.
Q4. What is an ionic bond ?
Ans: The electrostatic attraction between the cation and anion is called the ionic bond.
Q5. Hydrogen is not a metal, yet it is placed in the activity series of metals. why ?
Ans. Like metals, hydrogen can lose an electron to form positive ion (H+).
Q6. Why is H2 gas not evolved when a metal is treated with nitric acid.
Ans. Nitric acid is a strong oxidising agent. It oxidises the H2 produced to water and itself gets reduced to some oxide of nitrogen, i.e. nitrous oxide (N2O), nitric oxide (NO).
Q7. Name two metals other than silver and gold which are not attacked even by steam.
Ans. Lead and copper.
Q8. What are minerals ?
Ans. The elementary state or the compounds in form of which the metals occur in nature, associated with impurities of gangue, etc. are called minerals.
Q9. What is an 'ore' ?
Ans. The mineral from which metal can be extracted conveniently and economically is called an ore.
Q10. What do you understand by 'thermite reaction' ?
Ans. The reduction of metal oxide to metal using aluminium as the reducing agent is called thermite reaction or aluminothermy.
Q11. Why aluminium does not occur in native state ?
Ans. Aluminium, being a reactive metal, combines with oxygen readily to form alumina.
Q12. What is the composition of stainless steel ?
Ans. Iron (74%), chromium (18%) and nickel (8%).
Q13. Name the metals which are usually alloyed with gold to make it harder.
Ans. Copper and silver.
Q14. What is meant by 22 carat gold ?
Ans. An alloy consisting of 22 parts by weight of pure gold and 2 parts by weight of copper or silver is called 22 carat gold.
Q15. Why is pure gold not suitable for making ornaments ?
Ans. Because, pure gold is soft and ductile.
Q16. Name a metal which is used for galvanising iron ?
Ans. Zinc.
Q17. Why is an iron grill painted frequently ?
Ans. To protect it from rusting.
Q18. Name two metals which are highly resistant to corrosion.
Ans. Platinum and gold.
Q19. The corrosion of iron is called... .
Ans. Rusting.
Q20. The process of depositing a thin layer of zinc on iron articles is called ........ .
Ans. Galvanisation.
Q21. State conditions for rusting of iron.
Ans. Presence of moisture and air.
Q22. Metals generally occur in solid state. Name and write the symbol of a metal that exists in liquid state at room temperature.
Ans. Mercury (Hg).
Q23. Alloy are used in electrical heating devices rather than pure metals. Give one reason.
Ans. Alloys generally have lower melting points than the constituent metals. Therefore, in case short - circuiting occurs, the alloy melts, electrical connection is broken and fire are avoided.

Cell

2018-03-26T07:41:00.002-07:00

Cell

The Cell,(comes from Latin word cella,meaning "small room") is the smallest unit of life. It is basic structural,functional, and biological unit of all living organisms.
Cell was discovered by Robert Hooke in 1665.
Cells are often called the "building blocks of life".
All plants and animals are made of cells.
Organisms are classified as Unicellular (consisting of single cell,such as bacteria) and Multicellular (consisting of multiple cells,such as Plants and Animals).
Number of cells are varies from species to species.Human contains more than 10 trillion cells.
Most of cells are visible only under microscope.

Types of cells
There are two types of cells:
Prokaryotic cells: Single celled organisms.
Doesn't contains Nucleus.
Eukaryotic cells: Single or multi cellular organisms.
Contains Nucleus.
Prokaryotic cells
The first form of life on Earth.
Prokaryotic cell is a unicellular organism lacking membrane bound organelles.
Most of prokaryotic cells are unicellular.They are generally small in size.
There Nucleur region is not well defined as they lack a Nucleus but it is known as Nucleoid.

Eukaryotic cells
Eukaryot are those organisms whose cells have a Nucleus and other organelles enclosed within membrane.
Eukaryotic organisms may be unicellular or multi-cellular and only Eukaryotes form multi-cellular organisms consists of many kinds of tissue made up of different types of cells.
They are generally larger in size.
Plants and animals cells are Eukaryotic cells.
Contains more than one chromosomes.

All cells posses DNA except for red blood cells.

Atom And Molecule

2018-03-26T07:40:00.000-07:00

Atom

An atom is the smallest unit into which matter can be divided without the release of electrically

charged particles.
It also is the smallest unit of matter that has the characteristic properties of a chemical element.
The atom is the basic building block of all matter.
Atoms are very small, they are smaller than anything that we can imagine or compare with.
More than millions of atoms when stacked would make a layer barely as thick as a sheet of paper.
Most of the atom is empty space.
The rest consists of a positively charged nucleus of protons and neutrons surrounded by a cloud of negatively charged electrons.

Atomic mass

Atomic mass is the average mass of atoms of an element, calculated using the relative abundance of isotopes in a naturally-occurring element.
Atomic mass indicates the size of an atom.
Although the mass is the sum of all the protons, neutrons and electrons in an atom.

Molecule

A molecule is in general a group of two or more atoms that are chemically bonded together, that is tightly held together by attractive forces.
A molecule can be defined as the smallest particle of an element or a compound that is capable of an independent existence and shows all the properties of that substance.
Atoms of the same element or of different elements can join together to form molecules.

Ion

Compounds composed of metals and non-metals contains charged species. The charged species are known as Ions.
An ion is a charged particle and can be negatively or positively charged.
Negatively charged ion is called an 'anion' and the positively charged ion, a 'cation'.
A group of atoms carrying a charge is known as a polyatomic ion.

Newton's Laws of Motion

2018-03-25T23:18:00.003-07:00

Force

Concept of force is central to all of physics whether it is classical physics,nuclear physics,quantum physics or any other form of physics
So what is force? when we push or pull anybody we are said to exert force on the body
Push or pull applied on a body does not exactly define the force in general.We can define force as an influence causing a body at rest or moving with constant velocity to undergo an acceleration.
There are many ways in which one body can exert force on another body
Few examples are given below
(a)Stretched springs exerts force on the bodies attached to its ends
(b)Compressed air in a container exerts force on the walls of the container
(c) Force can be used to deform a flexible object
There are lots of examples you could find looking around yourself
Force of gravitational attraction exerted by earth is a kind of force that acts on every physical body on the earth and is called the weight of the body
Mechanical and gravitation forces are not the only forces present infact all the forces in Universe are based on four fundamental forces
(i) Strong and weak forces: These are forces at very short distance (10^-05 m) and are responsible for interaction between neutrons and proton in atomic nucleus
(ii) Electromagnetic forces: EM force acts between electric charges
(iii) Gravitational force -it acts between the masses
In mechanics we will only study about the mechanical and gravitational forces
Force is a vector quatity and it needs both the magnitude as well as direction for its complete description
SI unit of force is Newton (N) and CGS unit is dyne where
1 dyne= 10⁰⁵ N

Newton's First law of Motion

· We have already stated Newton's First law of motion which says that a body would continue to be in state of rest or continue to move with constant velocity unless acted upon by a net external force

· Here the net external force on the body is the vector sum of all the extenal forces acting on the body

· When the body at rest or in a state of motion with uniform velocity then in both the cases acceleration is zero.This implies that
a=0 for F=0

· When net forces i.e vector sum of all the forces acting on the body is zero.the body is said to be in equilbrium .When rotational motion is involved <,net torque on body should also be zero i.e their is no change in either translational or rotational motion

· Since forces can be combined according to the rules of vector addition.Thus for a body to be in equilibrium
R=ΣF=0
or in component form
ΣF_x=0
ΣF_y=0
These are the condition for the body in translational equilibrium

· We will discuss about rotational equilibrium while studying torque and rotational motion

· Thus Newton's First law of motion quantitatively defines the concept of force as a influence that changes the state of motion of the body

· It does not say anything about what has to be done to keep object moving that is once the body gains motion by the application of force would it always remains in the state of motion or it would come to rest

· According to first law if we completely eliminates frictional forces, no forward force at all would be required to keep an object ( say a block on table) moving once it had been set in motion

Inertia and Mass

· From First law of motion an object at rest would not move unless it is acted upon by a force

· This inherent property of objects to remain at rest unless acted upon by a force is called intertia rest

· Now consider the case of an object moving with uniform velocity along the straight line .Again from Newton's law it would continue to move with uniform

· This inherent property by virtue of which a body in state of uniform motion tend to maintain its uniform motion is called inertia of motion

· Combining these two statements 'The property of an object to remain in state of rest or uniform rectilinear motion unless acted upon by a force is called inertia'

· Mass of any body is the measure of inertia .For example if we apply equal amount of force on two objects of different mass (say m₁ and
m₂ such that m₁ > m₂ ) then acceleration of both the object would be different (i.e , a₁ < a₂ )

· Acceleration of object having larger mass would be lesser then the acceleration of object having smaller mass

· Thus larger the mass of the body ,smaller would be the acceleration and larger would be the inertia

· Newton's first law of motion revealing this fundamental property of matter i.e inertia is also known as law of inertia

Newton's second law of motion

Newton's first law of motion qualitatively defines the concept of force and the principle of inertia
For an body at rest, application of force causes a changed in its existing state and application of force on a body moving with uniform velocity would give the body under consideration as acceleration
Newton's second law of motion is a relation between force and acceleration
Newton's second law of motion says that
" The net force on a body is equal to the product of mass and acceleration of the body"
Mathematically
F_net=ma (1)
Where F_net is the vector sum of all the forces acting on the body
Above equation -(1) can be resolved along x,y and z components .Thus in component form
F_netx=ma_x
F_nety=ma_y
F_netz=ma_z
Component of acceleration along a given axis is caused only by the net component of force along that axis only not by the components of force along other axis
Newton's second law of motion is completely consistent with newton first law of motion as from equation (1) F=0 implies that a=0
For a body moving under the influence of force, acceleration at any instant is determined by the force at that instant not by the previous motion of the particle
Newton's second law of motion is strictly applicable to a single particle .In case of rigid bodies or system of particles, it refers to total external forces acting on the system excluding the internal forces in the system.

Newton's third law of motion

· Statement of newton's third law of motion is " To every action there is always an equal and opposite reaction".

· Thus,whenever a body exerts force on another then another object exert an equal force on previous body but in opposite direction

· Force example motion of rocket depends on the third law of motion i.e, action and reaction .Rocket exerts action force on gas jet in backward direction

· Force of action and reaction acts on different objects i.e,
Force object 1 exerts on object 2= Force object 2 exerts on object 1
i.e,
F₁₂=-F₂₁
Action=-(Reaction)

· According to Newtonian mechanics force is always a mutual interaction between the bodies and force always occurs in pairs

· Equal and opposite mutual forces between two bodies is the basic idea between Newton's third law of motion

· While considering a system of particles ,internal force always cancel away in pairs i.e consider two particles in a body if F₁₂ and
F₂₁ are internal forces between particle system 1 and 2 then they add up to give a null internal force.Same way internal forces for the particles

Applying Newton's law of motion

· Newton's law of motion ,we studied in earliar topics are the foundation of mechanics and now we look forward to solve problems in mechanics

· In general, we deal with mechanical systems consisting of different objects exerting force on each other

· While solving a problem choose any part of the assembly and apply the laws of motion to that part including all the forces on the chosen part of the assembly due to remaining parts of the assembly

· Following steps can be followed while solving the problems in mechanics
1)Read the problem carefully
2) Draw a schematic diagram showing parts of the assembly for example it may be a single particle or two blocks connected to string going over pulley etc
3) Identify the object of prime interest and make a list of all the forces acting on the concerned object due to all other objects of the assembly and exclude the force applied by the object of prime interest on the other parts of the assembly
4) Indicate the forces acting on the concerned object with arrow and Label each force for example tension on the object under consideration can be labeled by letter T
5) Draw a free body diagram of the object of interest based on the labeled picture.Free body diagram for the object under consideration shows all the forces exerted on this object by the other bodies.Do not forget to consider weight W=mg of the body while labeling the forces acting on the body
6) If additional objects are involved draw separate free body diagram for them also
7)Resolve the rectangular components of all the forces acting on the body
8) Write Newton second law of equation for the body and solve them to find out the unknown quantities
9) Do not forget to employ Newton's third law of motion for action reaction pair which results in null resultant force

· Following solved example would clearly illustrate how to apply Newton's laws of motion following the above given procedure

Nutrition

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Nutrition

Nutrition is defined as the process of intaking of nutrients and its utilisation by an organism in various biological activity.

Modes of Nutrition

1. Autotrophic
2. Heterotrophic
Autotropic nutrition: Auto = self, Trophic = nutrition. The literal meaning of this term is self nutrition.
Autotrophic Nutrition is a process where the organism prepare their own food from the simple inorganic materials like carbon dioxide, water and mineral salts in the presence of sunlight. All the green plants possess autotrophic mode of nutrition.
The autotrophic organisms contains green pigment known as chlorophyll. It is capable of trapping sunlight and this trapped energy is utilized by the autotrophs to prepare their food, combining carbon dioxide and water by the process of photosynthesis. This results in forming of glucose.
Heterotrophic nutrition: Heterotrophic nutrition is the mode of nutrition in which organisms depend upon another organisms to survive. All animals and non green plants are heterotrophic.
Types of heterotrophic nutrition:
Heterotrophic mode of nutrition is divided into following two types:
1. Saprophytic nutrition
2. Parasitic nutrition
Saprophytic nutrition: In saprophytic nutrition the organisms obtain their food from dead and decaying organic matter of dead plants, dead animals and other decomposing organic matter. And the organisms which obtain their food from dead and decaying organic matter of dead plants, dead animals and other organic matter are called saprophytes.
e.g. Fungi, bread mould, some protists and many bacteria are saprophytic in nutrition.
Forest Danger Cap Colorful Fungus Fly Fungi Fall
Parasitic nutrition:

In this type of nutrition, the organisms (called parasites) depend on the body of other living organisms (called their host) for getting their food.Many viruses, bacteria, fungi and animals have this mode of nutrition.

The organisms which depend on other living organisms (host) for food are called as parasites.
Parasites of two types:

a) Ecto parasites

b) Endo parasites

Ecto parasites

Ecto parasites are those parasites which obtain their food from their host by remaining outside the body of their host. For example, mosquitoes, ticks, lice and bed bug.

Endo parasites

Endo parasites are those parasites which obtain their food from their host by remaining inside the body of their host. For example, Ascaris, plasmodium vivax and tape worm.

Autotrophic Nutrition Heterotrophic Nutrition

Microorganism

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Microorganism

Microorganisms are microscopic, living, single-celled organisms such as bacteria. Ubiquitous throughout the world, microorganisms play a vital role in supporting and maintaining nature and life. The vast majority are beneficial: They keep nature clean by removing toxins from water and soil, and degrade organic matter from dead plants and animals. In the human body they aid in digestion and help prevent invasion by harmful bacteria. Without bacteria, life would not be possible.

Key Points

i) Microorganisms are divided into seven types: bacteria, archaea, protozoa, algae, fungi, viruses, and multicellular animal parasites (helminths).
ii) Each type has a characteristic cellular composition, morphology, mean of locomotion, and reproduction.
iii) Microorganisms are beneficial in producing oxygen, decomposing organic material, providing nutrients for plants, and maintaining human health, but some can be pathogenic and cause diseases in plants and humans.

Bacteria

Bacteria are unicellular organisms. The cells are described as prokaryotic because they lack a nucleus. They exist in four major shapes: bacillus (rod shape), coccus (spherical shape), spirilla (spiral shape), and vibrio (curved shape). Most bacteria have a peptidoglycan cell wall; they divide by binary fission; and they may possess flagella for motility. The difference in their cell wall structure is a major feature used in classifying these organisms.
According to the way they obtain energy, bacteria are classified as heterotrophs or autotrophs. Autotrophs make their own food by using the energy of sunlight or chemical reactions, in which case they are called chemoautotrophs. Heterotrophs obtain their energy by consuming other organisms. Bacteria that use decaying life forms as a source of energy are called saprophytes.

Archaea

Archaea or Archaebacteria differ from true bacteria in their cell wall structure and lack peptidoglycans. They are prokaryotic cells with avidity to extreme environmental conditions. Based on their habitat, all Archaeans can be divided into the following groups: methanogens (methane-producing organisms), halophiles (archaeans that live in salty environments), thermophiles (archaeans that live at extremely hot temperatures), and psychrophiles (cold-temperature Archaeans). Archaeans use different energy sources like hydrogen gas, carbon dioxide, and sulphur. Some of them use sunlight to make energy, but not the same way plants do. They absorb sunlight using their membrane pigment, bacteriorhodopsin. This reacts with light, leading to the formation of the energy molecule adenosine triphosphate (ATP).

Fungi

Fungi (mushroom, molds, and yeasts) are eukaryotic cells (with a true nucleus). Most fungi are multicellular and their cell wall is composed of chitin. They obtain nutrients by absorbing organic material from their environment (decomposers), through symbiotic relationships with plants (symbionts), or harmful relationships with a host (parasites). They form characteristic filamentous tubes called hyphae that help absorb material. The collection of hyphae is called mycelium. Fungi reproduce by releasing spores.

Protozoa

Protozoa are unicellular aerobic eukaryotes. They have a nucleus, complex organelles, and obtain nourishment by absorption or ingestion through specialized structures. They make up the largest group of organisms in the world in terms of numbers, biomass, and diversity. Their cell walls are made up of cellulose. Protozoa have been traditionally divided based on their mode of locomotion: flagellates produce their own food and use their whip-like structure to propel forward, ciliates have tiny hair that beat to produce movement, amoeboids have false feet or pseudopodia used for feeding and locomotion, and sporozoans are non-motile. They also have different means of nutrition, which groups them as autotrophs or heterotrophs.

Algae

Algae, also called cyanobacteria or blue-green algae, are unicellular or multicellular eukaryotes that obtain nourishment by photosynthesis. They live in water, damp soil, and rocks and produce oxygen and carbohydrates used by other organisms. It is believed that cyanobacteria are the origins of green land plants.

Viruses

Viruses are noncellular entities that consist of a nucleic acid core (DNA or RNA) surrounded by a protein coat. Although viruses are classified as microorganisms, they are not considered living organisms. Viruses cannot reproduce outside a host cell and cannot metabolize on their own. Viruses often infest prokaryotic and eukaryotic cells causing diseases.

Multicellular Animal Parasites

A group of eukaryotic organisms consisting of the flatworms and roundworms, which are collectively referred to as the helminths. Although they are not microorganisms by definition, since they are large enough to be easily seen with the naked eye, they live a part of their life cycle in microscopic form. Since the parasitic helminths are of clinical importance, they are often discussed along with the other groups of microbes.

1.In autotrophic nutrition organism prepares its food from simple substances present in the surroundings .	1.In heterotrophic nutrition organism obtains food from digesting organic compounds .
2.Autotrophs are the producers in the food chain .	2.Heterotrophs are the consumers in the food chain .
Example : Plants obtain food by autotrophic nutrition .	Example : Some plants and all animals obtain food by heterotrophic nutrition .
3.Autotrophs are fundamental to the food chains of all ecosystems in the world. They take energy from the environment in the form of sunlight or inorganic chemicals and use it to create energy-rich molecules such as carbohydrates. This mechanism is called primary production.	3.Organisms, called heterotrophs, take in autotrophs as food to carry out functions necessary for their life. Thus, heterotrophs are — all animals, almost all fungi, as well as most bacteria and protozoa — depend on autotrophs, or primary producers, for the energy and raw materials they need.
Types of Autotrophic nutrition: (i)Phototrophic (ii) Chemotrophic	Types of Heterotrophic nutrition : (i) Holozoic (ii) Saprophytic (iii)Parasitic and (iv) Symboitic Association