AS and A level Physics notes and revision

Samll phyisics exam point

2012-04-20T20:57:00.000-07:00

Look carefully
dispalacement travelled in t seconds is different from disaplacement travelled in t th second .

Heat

2012-04-15T06:24:00.000-07:00

The relationship between linear expansivity and area expansivity:

The linear expansivity of a material is equal to half times the area expansivity of a material.
HENCE area expansivity =2 x linear expansivity

The relationship between linear expansivity and volume expansivity:

The linear expansivity of a material equals to one third of the volume expansivity of the material.

HENCE volume expansivity = 3 x linear expansivity

These relationships should be remembered , because in the question only one form of linear expansivity will be given and you have to deduce the other forms.

Radioactivity

2012-04-15T02:32:00.000-07:00

Todays chapter is all about 'Radioactivity' its very important in science exams

Radioactivity
Radioactivity is the change in the nucleus of the atom of an element
There are three different types of radioactivity
They are:

alpha [ ] radiation
Beta [ ] radiation
Gamma [ ] radiation
When the nucleus emit these radiation the nucleus changes and a new atom of a different element is formed
Alpha radiation
1) It is giving out helium nucleus

When this is given out the mass number of the nucleus decreases by 4 and the atomic number decreases by 2
2) Its penetrating power is very low it can’t pass through even thin paper but a thin metal sheet can stop it.
3) It is heavier than beta
4) It is deflected by electric and magnetic field.

Beta radiation
1) One neutron in the nucleus changes to proton and electron and electron is given out as beta radiation
When this is given out the mass number of the nucleus does not change. The atomic number increases by 1
2) The penetrating power is higher than alpha particle. It can penetrate few centimeters of thin aluminum sheet but it can’t penetrate few centimeters of lead
3) It is light. It is deflected by electric and magnetic field

Three types of equilibrium

2012-04-13T02:52:00.001-07:00

1.neutral equilibrium| eg a ball on a flat surface
2.stable equilibrium eg a ball in a downward curved surface
3.unstable equilibrium eg a ball on a moutain curved surface

Main types of thermometers and their specific uses

2012-04-12T08:37:00.002-07:00

1.mercury glass thermometer- easy to use and take readings as the reding are already marked on the thermometer itself.

2.Gas thermometer - very sensitive and accurate as the expansion of gas is very high

3.Platinum wire resistence thermometer -measure temperatures that have a steady value
(mycar is used here because it is an good electric insulator but very fine conductor of heat)

4.Thermocouple - measure temperature at a point and also temperatures which are rapidly changing.

All the concepts of waves that are required for A Level Physics in animation form and very interactive

2011-10-19T08:27:00.000-07:00

Welcome to the animated are of this blog where learning becomes fun.
All the knowledge and stuff that you will need to learn in your A Levels when studying waves and their property and oscillations are presented below in a animated way.Learn and enjoy.

Ppa6 Concep Tests Ch 11

What are our main purposes for the use of satellites ?

2011-10-17T08:04:00.001-07:00

1.To transmit telecommunication messages to and fro .
2.To get weather news.
3.To get photos of the solar system or other planets.
4.

Waves and vibrations:

2011-10-09T21:38:00.001-07:00

Speed of a wave= frequency x wavelenght of the wave
period =1/frequency

Light waves and transverse waves and sound waves are longitudinal waves.

If you still need any more information, please leave a cooment.

A Level Physics :Vectors and thier addition with Force

2011-10-02T06:28:00.000-07:00

The maximum value of a resultant force when two forces act on a body = Force 1+ Force2
The minimum value of a resultant force when two forces act on a body= Force1 - Force2

The resulatant force of two forces that act in many diverse direction.

Pressure

2011-10-02T05:51:00.000-07:00

The physical equation for pressure is Pressure = force/are Pressure is measured in Pascals.

Below is a graphical explanation for pressure , please give me your views by commenting!

This picture was taken by me in karainagar with a digital camera and is protected by copyright.

when the force on a constant area increases the pressure also increases
When the area on which a constant force is applied decreases the pressure increases.

A Level Physics notes ans questions: Equation of continiuty

2011-09-30T07:23:00.000-07:00

The equation of continuity says that the rate of mass flow through a given tube at the entrance and at the exist is the same, if there is no other way for the fliud to get out from the pipe. Lets put things into a simpler form :

A1 x V1= A1 x V1

Lets prove this equation:

Mass flow rate = mass flowing through the pipe in one second
= V x D /t (t=1 second)
= l x a x D /t
= A x D x V ( l/t)
Because the mass flow rate is constant from th equation of continiuty
A1 x V1 x D = A2 x V2 x D

Equation of continuity and Bornoulllis law A Level Physics Notes Questions Answers and Explanation

As Density D is the same on both sides ,it gets canceled out.

So :,
A1 x V1 = A2 x V2

You must be able to prove this equation , and using this equation you will be able to solve many problems in your A Level Physics exam paper.

For a set of questions and Answers onthis section of A Level Physics Please click here.

A Level Physics:Dynamics and Motion(formula and solved problems)

2011-09-29T07:28:00.001-07:00

Dynamics Physics a level Motion in a srtraight line. Speed is different from velocity .Speed is the distance moved in a unit time , while velocity is the distance moved in a unit time in a particular direction. We can assume that a car is moving in a stright line with a velocity of 5 m/s ,than it is evident that the car travels a distance of 5m in one second without any change in direction, The equation which is used is: velocity = distance moved /time taken (use this formula in exams and when doing problems) Example: A motor bike travels 1000 m in 6 minutes,find the speed of the motor bike? (dear students take note of the wording please the question asks for the speed of the bike as it doesnot say that the bike travelling in a specific direction. If you have any further doubts about the specifications about the differenciations of speed and velocity and the problems involved in them please be kind enough either to email me at veeradinesh85@gmail.com or just leave a comment below.Any type of doubts are welcome even ifthey are not from this section.

A Level Notes: Law of Floatation

2011-09-29T07:26:00.000-07:00

The principle of floatation says that for a floating objects,the weight of the object equals the upthhrust exerted by a fluid on that object.
ie: When a body floats in a liqiud , it is in equilibrium and is acted upon by two forces only,its weigght and the upthrust.

These two forces must be equal and opposite to satisfy the conditions of floatations,

Weight of object = upthrust

But as we already know from Archimedes principle that U=Vx Dx g N..............................1

So hence, Weight=VDg..........................2

With these two equations you must be able to solve problems on the law of flatation,

I wish you all the best in your exam.If you need any other notes or information in this topic or any other area of physics email me or simply put a comment.

Weights and Mass A Level Physics

2011-09-23T07:01:00.000-07:00

The weight of an object is defined as the force acting on it due to the gravitational force .The weight of a object can be measured by attaching it to a spring balance and reading the scale.

But mass is differen in the way that it is equal to the density of the object multiplied by the volume of the object.
Mass is universally constant meaning it doesnot change from one planet to the other just as weight changes.

(a level revision,notes,syllabus,problems solved,help,tutorial)

2011-09-23T06:45:00.001-07:00

Hydrostatics.
This is the study of fliuds and their behaviors.

Circular motion Physics A Level

2011-09-06T04:27:00.000-07:00

Circular Motion

What is exactly meant by circular motion ? It is the physical motion of an object moving in a circular path about a center. There are circular motion in many areas of our life, for example the hour and minute hand of a clock displays circular motion, and also the planets and moons in the solar system show circular motion.(Although planets move in elliptical paths we consider them to be moving in circular paths for calculation purposes.)

First lets look at some important maths that are a essential for understanding todays topic of circular motion.

180 degrees = π radians

360 degrees = 2π radians

90 degrees = ½ π radians

For very small angles : sin θ = θ radians

tan θ= θ radians

* Ѡ (the angular velocity) is the angle in radians through which the the object in circular motion has turned in one second.

*ἀ (the angular acceleration) is the increase in the value of Ѡ (the angular velocity) per second.

* r –denotes the radius of the circle that we are dealing with.

The types of circular motion:

1. Horizontal circular motion

2. Vertical circular motion

3. Conic pendulum

Different situation or means of circular motion:

1. Revolving at a constant speed around a circle.(eg: hands of a clock)

2. Revolving with variable speeds (that is with constant angular acceleration or constant angular deceleration)

*(eg : A car starts from rest and its wheels show constant angular acceleration)

1. Constant speed circular motion:

A particle P revolves at a constant speed in a circular path. At time ( t=0), P is at P₁. After a time t , P is there as shown in the diagram. Consider the radius of the circular path to be r.

S=r θ (θ in radians)

Velocity

V=s/t

V=r θ/t (from equation 1)

θ/t= Ѡ (angular speed)

Ѡ= θ/t

(linear velocity) V= r Ѡ ( angular velocity)

Definition of angular speed:

The rate of change in angle is the angular speed.

The unit of angular speed is rad/s.

The Dimension of angular speed is T^-1

Angular speed is a scalar quantity because it has only a magnitude.

Angular velocity id a vector quantity ,because it has both direction and magnitude.

Rotation with a constant speed:

If a body is rotating with a constant speed then tangential acceleration is equal to zero.But still there an acceleration on the body toward the center. THIS IS CALLED CENTRIPETAL ACCELERATION!

Errors and their types:

2011-09-05T09:42:00.000-07:00

Errors can be grouped into two groups :
1 systematic error

systematic: e.g. constant error (in all readings)
cannot be eliminated by averaging
error in measuring instrument B1

2.random errors
random: e.g. readings scattered (equally) about true value
error due to observer
can be eliminated by averaging
(only if averaging not included for systematic

It is very to know these by heart as you will be given a direct question about errors in your physics AS exam.

2011-09-05T09:41:00.001-07:00

Projectile motion A level Physics

2011-09-04T03:08:00.000-07:00

Projectile motion is a special case of two dimensional motion with constant acceleration. Here, force due to gravity moderates linear motion of an object thrown at certain angle to the vertical direction. The resulting acceleration is a constant, which is always directed in vertically downward direction.
read the rest at http://cnx.org/content/m13837/latest/
Problems on Projectile motion can either start from the botom with an object thrown at a angle witha speed.or it can startfrom a height like a cliff with the object either thrown upward or horrizontally with an initial speed.Which ever the problem is about the following formulas can be used to tackle the questions..

Remember these formulas for doing problems on projectile motion:

The maximum Height that the particle has travelled = u2sin2o(theta)
2g
The time taken for the particle to reach the ground again = 2u sino
g
Range = u2sin2o
g

Todays question: about Deriving a SI unit

2011-09-03T00:43:00.000-07:00

Expresse the volt in terms of SI base units?

Ok lets get started:
We know that P=VxI
Fx d=VxI
F is kgm/s2 d is in m and I is in A
So V= kgm2s-2A-1

If you need anymore help in deriving the SI units of other quantities just leave a comment and I shall reply.

Lets do a physics question (a level)

2011-09-01T09:46:00.001-07:00

Lets do a physics question (a level)

welcome back

The question is as follows

Q:A laser emits light of wavelength 600 nm
. What is the distance, expressed as a number of wavelengths, travelled by the light in one second?

We know that

1 nm=10^-9m
therefore: 600nm =6 x 10^-7m

we also know that the speed of light is= 3 x 10 ⁸m/s
so v= f x L

note that the question asks for the frequency

so: f= 3 x 10⁸/6 x 10^-7 Hz
the answer is f= 5 x 10¹⁴ Hz

The important formulas and values that you must know for exams and to solve problems:

2011-08-31T21:12:00.001-07:00

Please take note of the following because they will be useful in your exams: Click on the images to see them clearly!

Problem on circular motion - solved

2011-08-31T08:00:00.001-07:00

the question:

An object of mass 4 kg moves round a circle of radius 6 m with a constant speed of 12 m/s.

Read the question first :

Calculate
1.the angular velocity
Answer: angular velocity= speed/readius
= 12/6
= 2 rad/s
ok this is done with the formula : angular velocity= speed/readius
the next question is
2.the force towards the center (using a=v2/r)

Answer: force = m a
= mx v2/r ok
= 4x 122/6
=96N

Rotational motion Physics A Level

2011-08-31T06:12:00.001-07:00

Todays topic is rotational motion .

Many students take this chapter to be a difficult one, but in fact it is a very easy one :the only thing we will have to do is to compare rotational motion with linear motion and then do the questions based on the formulas we are going to derive:

Torque is considered as the force here and alpha that is angular acceleation is considered to be acceleration.

Torque is considered as the force here and alpha that is angular acceleation is considered to be acceleration

Torque= force x radius of circle

Rotational motion Physics A Level

2011-08-31T06:09:00.000-07:00