Physics Experiment, Practical drawing, Animation free download for std 8 to 12

Micrometer, its construction, reading ITI fitter, Std 11

2012-10-19T18:30:00.003+05:30

Micrometer (Screw Gauge)

Introduction

Micrometer screw gauge is a form of calipers used for measuring small dimensions. Screw gauge in extensively used in the engineering field for obtaining precision measurements. The article describes the principle and main parts of a basic micrometer screw gauge.

Micrometer screw gauge (or micrometer caliper) is an instrument or device for measuring the length of an object which is more precise than a ruler and vernier caliper. It because a micrometer screw gauge has the smallest scale of 0.01 mm. The device is widely used in mechanical engineering for measuring small diameter, thickness, or angles to a high degree of accuracy.

More details video :

Micrometer (Screw Gauge) its construction and How to take reading.
or paste this link : http://youtu.be/6KI7cI0Xb6c

Construction and Parts

Thus the main parts of a micrometer screw gauge are:

Micrometer Frame

Frame :

Made up of Dropped Forged steel or Malleable Steel. All other parts joint with frame.

Micrometer Anvil

Anvil :

Most important parts of Micrometer, which is made up of Alloy steel, hardening, tempering and finishing is done very accurately.

Micrometer Spindle

Spindle :

Is made up of Nickel Chrome metal, which is also hardened, Grind and accurately made. Which is move to and fro as we rotate thimble. The maximum displacement of spindle is 25 mm.

Micrometer Measuring faces

Measuring faces :

Both the end of Anvil and Spindle, Measuring face is fixed, which is made from Alloy steel, as well as hardened, grind and accurately finished.

Micrometer Barrel or Sleeve

Sleeve :

The Barrel or sleeve is connects the frame to the cylindrical tube. It is a non-movable part of the screw gauge and has a scale inscribed over it which is the main scale of the device. Moreover, it also carries the most important part of the micrometer- the screw.

Micrometer Thimble

Thimble :

The thimble or head is the end of the cylindrical tube and is turned to move and adjust the spindle. The thimble carries the Micrometer or secondary scale.

Micrometer Ratchet

Ratchet :

There is one more part called the ratchet which is provided at the end of the tube. The ratchet is kind of limiting device which applies a pressure by slipping at a predetermined torque and thus prevents the spindle from moving further.

Micrometer Spindle lock nut

Screw Lock :

screw gauges also consist of locking devices which holds the scales at a particular position for prevent any kind of error while taking readings.

A screw gauge consists of a “U” shaped metallic structure, which is attached to a hollow cylindrical tube on one end. The hollow tube has a uniformly threaded nut inside it. A long stud with a plane face is fitted into this nut. Exactly on the opposite side of this nut and on the other end of the U shaped frame, a smaller stud with a plane face is also attached. Faces of both the studs are exactly parallel to each other.

This U shaped metallic structure is known as the frame of the micrometer screw gauge. The smaller stud is known as the anvil and the longer one is known as the spindle. The anvil is the fixed part of the device, whereas the spindle moves as and when the head is moved. The frame carries both the anvil and barrel, and is also heavier than the rest of the parts. The object to be measured is held between the anvil and the spindle.

The Barrel or sleeve is connects the frame to the cylindrical tube. It is a non-movable part of the screw gauge and has a scale inscribed over it which is the main scale of the device. Moreover, it also carries the most important part of the micrometer- the screw.

The screw is the heart of the micrometer and is located inside the barrel. The screw converts small dimensions into measurable distance using a scale. The thimble or head is the end of the cylindrical tube and is turned to move and adjust the spindle. The thimble carries the vernier or secondary scale. There is one more part called the ratchet which is provided at the end of the tube. The ratchet is kind of limiting device which applies a pressure by slipping at a predetermined torque and thus prevents the spindle from moving further. Some screw gauges also consist of locking devices which holds the scales at a particular position for prevent any kind of error while taking readings.

A micrometer screw gauge also uses two scales – main and secondary scales. The secondary scale is provided on the thimble and is the measurement of the pitch of the screw. This means that the reading on the secondary scale measures the distance moved by the thimble per rotation. The scale on thimble is divided into 100 equal parts and measures hundredths of a millimeter. The thimble scale rotates over the spindle or the main scale. The main scale is a millimeter scale subdivided into equal parts with half a millimeter distance. When the object is to be measured, it is placed in between the anvil and the spindle. Readings from both the scales are taken into account for arriving at the final measurement.

Micrometer screw gauge is a delicate device and thus special care should be taken while handling it. Moreover, it is also important that the micrometer is well calibrated to prevent any kind of error in the final reading.

Precaution Steps

The spindle and anvil are cleaned with a tissue or cloth, so that any dirt present will not be measured.

The thimble must be tightened until the first click is heard.

The zero error is recorded.

Reading = Reading of main scale + Reading of thimble scale.

While taking a reading, the thimble is turned until the wire is held firmly between the anvil and the spindle.

The least count of the micrometer screw can be calculated using the formula given below:

Use the given formula:

Least Count (L. C) = Pitch/no. of divisions on micrometer barrel(thimble)

where,

Pitch = distance travelled by thimble on linear scale in one rotation.

Least count = 0.01 mm

Types of error in micrometer screw gauge reading

Every micrometer prior to its use should be thoroughly checked for backlash error or zero error.

Backlash error:

Sometimes due to wear and tear of the screw threads, it is observed that reversing the direction of rotation of the thimble, the tip of the screw does not start moving in the opposite direction immediately, but remains stationary for a part of rotation. This is called back lash error.

Zero error:

If on bringing the flat end of the screw in contact with the stud, the zero mark of the circular scale coincides with the zero mark on base line of the main scale, the instrument is said to be free from zero error. Otherwise an error is said to be there. This can be both positive and negative zero error.

Calculating micrometer screw gauge reading:

Total observed reading = main scale reading + (circular scale division coinciding the base line of main scale) x least count

True diameter = observed diameter – zero error

Example, main scale reading = 2mm or 0.2cm

Circular scale reading = 56, so 56 x 0.001 = 0.056cm

So observed reading = 0.2 + 0.056 = 0.256cm

Post office box Experiment for std 8 to 12 Physics

2012-07-06T16:53:00.003+05:30

POST OFFICE BOX

Aim:-

A post office box and other necessary instruments are given to you. Take three appropriate ratios of the resistances in the two arms of Post Office Box and determine the values of two unknown resistances.

Now connect the unknown resistances in series and parallel respectively and verify the laws of series and parallel combinations of resistances.

PRINCIPLE :-

It works on the principle of balanced Wheatstone bridge.

APPARATUS :-

A Battery,

unknown resistance (Rx & Ry),

Post Office Box,

a galvanometer,

rheostat,

connecting wires.

Post Office Box Apparatus

Condition 1 Resistance Rx connect between C and D

Post Box Wiring Diagram find Unknown Resistance Rx

Condition 2 Resistance Ry connect between C and D

Post Box Wiring Diagram find Unknown Resistance Ry

Post OfficeBox line diagram Series connection Rx and Ry

Series connection of Rx and Ry wiring diagram

Parallel Connection line Diagram of Rx and Ry

Wiring Diagram Parallel connection of Rx and Ry

CALCULATIONS :-

Series connection, R’s = Rx + Ry + …..Ohm

Parallel connection, R’p = Rx Ry / Rx + Ry = ….Ohm.

RESULT :-

(1) Unknown resistance, Rx = ….Ohm. , Ry = ….Ohm

Observation for Post Office Box Experiment

Calculation table for Post Office Box

CONCLUSION :

The experimental and theoretical values of equivalent resistance for series and parallel connections are equal,within the experimental error. This implies the validity of the rules for the different combinations of resistances.

Precautions

All plug keys of Post Office Box must be tight.

Contact points of K1 and K2 must be cleaned with sand paper.

Galvanometer should be very sensitive.

Throughout the experiment press key K2(battery key) first and then key K1(galvanometer key).

More Video : Post Office Box Video presentation.

http://youtu.be/vG1Bkh1V7RY

Post Office Box Experiment.

Prepare Ammonia gas in Laboratory science 8 to 12

2012-06-10T08:32:00.000+05:30

18 . To prepare ammonia gas in the laboratory and study its properties.

AIM : To prepare ammonia gas in the laboratory and study its properties

THEORY : On heating a mixture of ammonium chloride and calcium hydroxide, we get ammonium gas.

APPARATUS : Big hard glass tube, delivery tube, hollow glass tube, Bunsen burner, glass rod, two single-holed rubber cork, four to five gas jar with lids, stand and one CaO bottle as shown in the figure.

CHEMICALS : Calcium hydroxide, ammonium chloride, concentrated hydrochloric acid, red and blue litmus papers.

Prepare Ammonia Gas in Laboratory

Observation
Colour of ammonia gas :
Odour or smell of ammonia gas :
Ammonia gas is collected by downhard displacement of air therefore it is than air.
Use moist red and blue litmus papers and check the effect on ammonia gas.

Conclude :
Wet red litmus :
Wet blue litmus :

Conclusion : What happens when a glass rod is dipped in concentrated HCL is brought near the mouth of gas jar containing ammonia ?

Exothermic reaction for std 8 to 10

2012-05-18T18:11:00.000+05:30

To measure the change in chemical reactions and conclude whether the reaction is exothermic or endothermic.

AIM : To measure the change in chemical reactions and conclude whether the reaction is exothermic or endothermic.

THEORY : During the chemical reaction if the temperature increases the reaction is exothermic and if temperature decreases the reaction is endothermic.

APPARATUS : Conical flask, 250 ml. Beaker, Stand, Thermometer, Glass rod, measuring cylinder, stirrer.

MATERIAL : Dilute hydrochloric acid, Zinc metal, Solid ammonium chloride,

Exothermic reaction

Observation :

(1) initial temperature of dilute hydrochloric acid 0 C.
(2) Temperature of the mixture when Zinc metal dissolves in hydrochloric acid = 0 C.
(3) Difference of temperature = 0 C.
(4) Give chemical reaction of Zinc metal with hydrochloric acid.

NOTE :

(1) Similarly heat of neutralization in neutralization reaction between dilute hydrochloric acid and sodium hydroxide can be measured.
(2) The increase in temperature can be noted when dissolution of solid sodium hydroxide in water is carried out.

PRACTICAL USES

The combustion reactions of kerosene,

Petrol,

LPG are exothermic,

therefore these substance are used as fuel.

Focal Length by an Image of far distance object for std 8 to 10

2012-05-13T17:57:00.000+05:30

To determine the focal length of a convex lens by obtaining an image of a far distance object.

AIM : To determine the focal length of a convex lens by obtaining an image of a far distance object.

PRINCIPLE : Rays parallel to the axis, after being refracted by a convex lens, are focused on the principal focus. Distance between the optical centre and the principal focus is known as the focal length.

APPARATUS : Convex lens, Stand, Screen, Foot-rule, etc,.

Focal length of a far distance object

Observation : Distance between the optical center of the lens and the image on the screen = Focal length of the lens f = cm...

Practical uses : Convex lens of proper focal length are used in optical instruments like simple microscope, compound microscope, telescope, etc,. Also the method given here in the simplest way to estimate the focal length of a convex lens.

Learning through Innovative technique picture

2011-11-17T08:46:00.000+05:30

http://www.flickr.com//photos/physics_for_fun/show/with/5279683649/

To determine the focal length of a concave mirror by far away image.

2011-07-07T21:29:00.000+05:30

2. To determine the focal length of a concave mirror by obtaining an image of a far distance object

AIM :- To determine the focal length of a concave mirror by obtaining an image of a far distance object.

APPARATUS :- A concave mirror of diameter approximately 10 cm., stand, screen, foot-rule, etc.

PRINCIPLE :- Rays coming from a far distance object are almost parallel. Such rays, parallel to the principal axis, after being reflected by a concave mirror, are focused at the principal focus of the mirror. Distance between the principal focus and the pole of the mirror is known as the focal length.

NOTE : Here screen should be taken small, so that rays coming from the object are not blocked by the screen itself. Diameter of the screen here can be approximately 3 – 4 cm.

Focal Length of Concave mirror

Parallal rays of a Image

Focal length of image on concave mirror

OBSERVATION

Distance between the pole of the mirror and the image on the screen = focal-length = CM.

CONCLUSION

PRACTICAL USES

Concave mirrors are used in head lights of vehicles, solar furnace, solar cooker, shaving mrror, etc. For all such applcatons it is necessary to know the focal length of the mirror to used. It can be estimated using the given method.

Video

To determine the focal length of a concave mirror by obtaining an image of a far distance object.

Focal length of concave mirror of a far away image.wmv

Angle of Incidence, Angle of image through Glass Slab experiments for std 8 to 12

2011-07-04T16:36:00.000+05:30

To draw the path of a ray passing through a glass slab and, hence, to measure the angle of incidence and the angle of image.

AIM : To draw the path of a ray passing through a glass slab and, hence, to measure the angle of incidence and the angle of image.

PRINCIPLE : When an oblique ray of light enters from one transparent medium to another transparent medium, at the surface separating these two media, the light ray changes its path. This phenomenon is called refraction of light. When a ray of light passes through a glass-slab, it is refracted twice, as a result of which, the emergent ray becomes parallel to the incident ray.

APPARATUS : Glass –slab, Drawing-board, Drawing paper (White), Foot-rule, Pencil, Pins, Push pins and Protractor.

Paper fit with pins and set Glass Slab

Ø Fix a white drawing-paper on the drawing board using push pins. Now place the glass-slab on it and mark its position PQRS by drawing its out-line using a pencil.

Draw Ray AB not perpendicular to PQ

Ø Now draw a ray AB such that it is not perpendicular to PQ. Fix two pins upright with separation of 2-3 cm on this ray.

See Image from another side and set P3 P4

Ø Now try to see the images of P₁ and P₂ from side RS and fix pins P₃ and P₄ upright so that images of P₁ and P₂ and pins P₃ and P₄ become collinear at their lower ends.

Remove pins and Glass slab

Ø Now remove the slab and the pins obtain emergent ray CD by drawing a line passing through marks of P₃ and P₄, which intersects RS at C.

Ø Join B and C to complete the path of the ray. Now draw a normal MN to the surface PQ in such a way that it passes through B. Also draw M’N’, through C to the surface RS.

Measure Angle of Incidence and Angle of Emergence.

Ø Measure ÐAMB (Angle of Incidence) and ÐOCN’ (Angle of Emergence).

By changing Angle of Incidence repeat the experiment

Ø Repeat the experiment for various values of angle of incidence AMB and note your observations in the table.

Angle of Incidence Video

Angle of Incidence, Emergence, Refraction through glass slab.wmv

Verify laws of Reflection using Plain Mirror Experiments with video presentation for std 10

2011-06-29T19:23:00.000+05:30

1. TO VERIFY THE LAWS OF REFLECTION USING A PLANE MIRROR

Aim : To verify the laws of reflection using a plane mirror.
Principle : When a ray of light is incident on a reflecting surface, it changes its direction of motion and travels in the original medium following certain laws. This phenomenon is called reflection of light.
Apparatus : Drawing board, a drawing paper (White), a plane mirror, a foot-rule, a pencil, four pins, four push pins, a protactor, a stand for the plane mirror.

Ø First of all fix the white drawing paper on the drawing board using push pins.

Pins up Paper on Wooden board

Ø First of all fix the white drawing paper on the drawing board using push pins. Place the plane mirror along with its stand and fix its position AB.

Verify Laws of Reflection using plain Mirror

Ø Now draw a line PQ which passes through the mid-point ‘P’ of AB and perpendicular to AB.

Ø PQ is called the normal to AB.

Law of Reflection Of Plain Mirror

Ø Draw a ray RP which makes some angle with the normal (PQ).

Ø Draw a ray RP which makes some angle with the normal (PQ). On the ray RP fix two pins P₁ and P₂ vertically with 2-3 cm separation between them. Ray RP is incident ray.

Reflection using Plain Mirror

Ø Now from the other side of PQ , (in which incident ray is not there) see the images of pins P₁ and P₂ fix other two pins P₃ and P₄ vertically so that pins P₃, P₄ and images P₁ and P₂ appears collinear at their lower ends.

To Verify Laws of Reflection using Plain Mirror

Ø Now remove the pins and the mirror. Join the marks of P₃ andP₄ and obtain the reflected ray PS.

Reflection by a Plain Mirror

Ø Repeat the experiment for different angles of incidence. Measure angle of incidence and angle of reflection. Note your reading in the observations table.

Observation of Reflection of Plain Mirror

Conclusion :

Practical Uses:

We can study the laws of reflection. We can also study the images obtained by the plane mirror. We can come to know how reflection is used in various optical appliances, e.g., periscope, keleidoscope.

Video :

To Verify the Laws of Reflection using Plain Mirror

HTML form making program, form of Registration, HTML registration form

2011-04-26T21:38:00.000+05:30

Make your own form programm Of HTML Registration for std 12.

Here is the sample of registration program, it is in simple way of making you understand, which you can develope yourself as per your design & requirements. for more sample program you can view the lable and find out your desire requirements.

<html>
<head>
<title>Whz kid Form</title>
<style type="text/css">
h1{font-size:26;
color:Blue;
font-family:Gujrati Saral-3;}
h3{font-size:15;
color:Red;
font-family:Times New Roman;}
lable { text-align:left;
width:130px;
display:block;
color:Green;
float:left;
clear:left;}
</style>
</head>
<body>
<form name="frm1" action="new.html" method="get">
<h1><center> xiKt iv2aly </center></h1>
<h3> Login Information </h3>
<lable for="username"> Username: </lable>
<input type="text "name="username " value="username "size="10"maxlength="10">
<br>
<lable for="email "> Email: </lable>
<input type="text" name="email " value="enter email here "size="25"maxlength="30">
<br>
<lable for=" password1"> Password: </lable>
<input type= "password " name="password1">
<small> must be 8-25 characters long </small>
<br>
<lable for="password2"> Confirm Password: </lable>
<input type="password" name ="password2 ">
<small> should match the password </small>
<br>
<h3> Other information</h3>
<lable for="name "> Name: </lable>
<input type="text" name="name">
<br>
<lable for="mobile"> Mobile No: </lable>
<input type="text" name="mobile">
<br>
<lable for="imageName"> Image:</lable>
<input type="file"name="ImageName">
<small> upload your image file(optional)</small>
<br>
<lable for="Country">Country:</lable>
<select name="Country" >
<option value="France">France</option>
<option selected value="India">India</option>
<option value="New Zeland">New Zeland</option>
<option value="United Kingdom">United Kingdom</option>
<option value="United States">United States</option>
</select>
<br>
<lable for="alertBy">Receive alert by:</lable>
<input type="radio" name="alert by" value="Email"checked>Email
<input type="radio" name="alert by" value="SMS">SMS <br>
<lable for="game"> Games of Interest:</lable>
<input type="checkbox" name="game" value="Shooting"checked>Shooting
<input type="checkbox" name="game" value="Puzzle">Puzzle
<input type="checkbox" name="game" value="Detective">Detective
<input type="checkbox" name="game" value="scrabble">Scrabble
<br>
<br>
<lable></lable>
<input type="Reset" value="Reset">
<input type= "Submit" value="Submit"><br>
</form>
</body>
</html>

Ohm's law Experiment presentation with Audio and Video for std 12 Physics

2011-03-25T17:57:00.000+05:30

Ohm's Law
AIM :-A voltmeter, a current meter, and an unknown resistance etc. are given to you. Prepare an appropriate circuit to verify Ohm’s law. With appropriate values of current and voltages, only with the help of calculations, determine the value of unknown resistance.
PRINCIPLE : Potential difference in a conductor produces electric current.
APPARATUS :-
A unknown resistance,
a voltmeter (0 - 10 V),
a milliammeter (0 - 500mA), a battery,
a rheostat,
a tap key,
connecting wires.

Internal Resistance of Primary Cell Experiment Potentiometer for std 12

2011-03-20T18:01:00.000+05:30

Internal Resistance of Primary cell With the help of Potentiometer
EXPERIMENT :- 7
Internal resistance of primary cell
AIM :
To find the internal resistance of a primary cell, by calculation and from a graph, with the help of a potentiometer.
PRINCIPLE :
It works on the principle of potentiometer.
Apparatus:
A potentiometer having a long (~400 cm) resistive wire of uniform cross-section, a battery E of 3 to 4 V, a primary cell ( dry cell or Laclanche cell or a Daniel cell), two rheostats [ 0 – 25 W (Rh1) and 0 – 500 W (Rh2) ], a galvanometer, a R.B.(0 – 50 W), two simple keys and a jockey.

Internal Resistance of Primary Cell Experiment Apparatus

Internal Resistance Of Primary cell wiring diagram experiment

Internal Resistance Of Primary cell Observation table

Internal Resistance Of Primary cell with graph

Internal Resistance Of Primary cell Slop Experiment

Internal Resistance of Primary cell With Potentiometer Experiment Video

Copper voltameter Experiment for std 12 Physics with animation Video

2011-03-20T17:26:00.000+05:30

AIM :-
Connect given copper voltameter in an appropriate circuit determine the electro chemical equivalent of copper.
PRINCIPLE :-
On passing electric current through CuSO4 solution, Cu+2 and SO-24 ions are separated or chemical effect of electric current.

APPARATUS :-
A copper voltameter,
6 V battery ( or D.C. Mains),
an ammeter,
a rheostat,
a simple key,
sand paper,
a stop-watch, balance,
weight box, etc.

Copper Voltameter Experiment Apparatus

PRECAUTIONS
The cathode plate should be throughly cleaned after rubbing with sand paper.
Pass only that much current as is obtained from the calculation of the area of the immersed part of the cathode plate.
Use only a fresh solution of CuSo4. To prepare the solution dissolve about 25 g of CuSO4 crystals in 100 cm3 water. Add a few drops of sulphuric acid (H2SO4) to make it more conducting.
Hold the plate from its upper end so as to avoid touching its surface.
Cathode plate should be washed immediately after it is taken out of the solution.

Copper Voltameter Experiment Line Diagram

Copper Voltameter Wiring Diagram for Std 12 Experiment

PROCEDURE :-

1. To Cathode plate dip in clean water, and wash off all the CuSO4, solution sticking to it. Thereafter wash it again with tap water.
2. Hold it in the sunshine for some time till it dries out. Now find out its mass by Physical balance.

Observation table for Copper Voltameter

Copper Voltameter Experiment Observation Table

Copper Voltameter Experiment Calculation

Copper Voltameter Experiment presentation Video.

Beautiful White material Monuments antique picture makes world nice

2011-03-14T19:22:00.000+05:30

When rising in the morning
take time to pray
Wisest thing to do
before you begin the day

Ask God for His blessings
for what the day may bring
He'll guard and keep you
in the midst of everything
Your day will be brighter
sweet peace will abide
Seek the Lord
you won't be denied

When d sun sets...pray again and thank d Lord 4 all d graces we rcvd 4 d day...reflect and ask 4gvness from our sins...

Angle of Prism, Physics practical for the standard 12

2011-02-14T15:22:00.000+05:30

REFRACTIVE INDEX OF PRISM

AIM:-

Determine with the help of pins, the angle of the given glass prism. Determine the values of angle of emergence and angle of deviation for four different values of angle of incidence. Hence prove that i + e = A +d.

PRINCIPLE :

Reflection and refraction of light.

PRECAUTIONS
While marking the position of a prism with pencil, the prism should not be disturbed.
A prism should be carefully put back exactly at the marked position.
While pressing the heads of the pins for fixing them use metal coin or a hard object so that you do not hurt your palm.
Do not press the pins very hard in the board otherwise it becomes difficult to remove them afterwards.
See that the pins pushed in the board remain perpendicular to the board.

Angle of Prism

Angle of Prism Conclusion

REFRACTIVE INDEX OF PRISM

AIM :-

Using pins with a given prism determine the angles of deviation for six different values of angle of incidence. Draw the graph of angle of deviation versus angle of incidence. Determine, from this the angle of minimum deviation and using following formula determine refractive index of material of the prism.

Angle of Prism Formula

Angle of prism, A = ……. .

Angle of Deviation measure

Angle of Deviation

Angle of Deviation Observation table

Angle of Deviation Graph

Waves

2011-02-01T20:23:00.000+05:30

" WAVES "

Wave
A wave is a disturbance that moves through a medium. The energy is transferred from one point to another without transport of any matter.

Frequency
It is the no. of waves passing through a point in the medium in one second (unit is Hertz).

Wave Length
The distance between two consecutive crests or two consecutive troughs is called wave length .
For the light waves, if the wave length is different, color of the light will be different.

Amplitude
The maximum displacement of the particle of the medium is called the amplitude of the wave.
When something vibrates it produces a sound. The energy of the the vibrations is passed on to the molecules in the surrounding air and makes them move. Thus the sound wave falls on the ear and the sound is heard. The stronger the vibrations, the longer the amplitudes and the louder the sounds.

Velocity
Wave velocity is the distance through which the wave moves in one seconds. Velocity of light is more than the velocity of sound, so in a thunderstorm, lightning will always be seen before the clap of thunder.

Waves Velocity

Waves are of two types

Transverse wave

If the displacement of the individual atoms or Molecules is perpendicular to the direction of the wave, the wave is called a Transverse wave ( light wave ).

Transverse wave

Longitudinal wave

If the displacement of the individual atoms or molecules is parallel to the direction of the wave, the wave is called a Longitudinal wave ( sound wave ).


Longitudinal wave

SOUND

STANDING WAVES

In a string fixed on both ends, when we strike or pluck at some point, waves propagate towards both ends & after reflection from the ends, overlap on each other to produce standing waves.

SOUND

STANDING WAVES

A violin string oscillates at a fundamental frequency.

Musical Instruments.

Wind instruments.

Standing wave can also be produced in air columns. In organ pipes(open at both ends), bugle & flute (closed at one end) and in tabla & dholak (closed at both ends) standing waves on air column produces sound.

Wind Instruments.

Different tones are produced by the same instrument depending on the type of vibrations. Here the fundamental & first two overtones are shown for both open end & closed at one end air column vibrations.

The wavelength (l) of the sound wave depends on the length (L) of the air column.

Wind instrument

String instruments.

The simplest form of string instrument is just a stretched string over a resonating body to amplify the sound.The standing waves produced in strucked string (piano) bowed string(violin)& plucked string (sitar & sarod) musical instruments produce a range of musical sounds.

Musical Instruments

AUDIBLE FREQUENCY RANGE

We can hear the sound if the frequency lies between 20 Hz. to 20 kHz. We hear low frequencies as low pitched and high frequencies as being high pitched.

AUDIBLE FREQUENCY RANGE

ULTRASONIC & SUBSONIC WAVES

Sounds above audible frequency are called ultrasonic and sounds below audible frequency are called infrasonic or subsonic sounds.

Elephants use very low-pitched sounds, below the level of human hearing ( subsonic sounds), that call other members of the heard over many miles.

ULTRASONIC & SUBSONIC WAVES

APPLICATIONS OF ULTRASONIC SOUNDS

1. Sonar receptors in Bats &Whales:- The bats & whales send out some ultrasonic rays, which bounce back from the prey and are received by this system and they can locate the prey.

Sonar receptors in Bats &Whales

2. Application in Medicine :- Instead of stethoscope ultra-sonography is used as a tool by physicians, to scan abdominal, pelvic and cardiac areas.

Application in Medicine

Ocean Depth

3. Ocean depth can be found by measuring the time between sending out an ultrasonic signal and receiving the echo reflected from the ocean bed.

Ocean depth

Detection of MINERAL OIL

4. Oil layer reflects a certain pattern of echoes which is detected by a seismograph.

Detection of MINERAL OIL

Doppler effect

As the car moves away,wave fronts of its whistle take longer time to reach a listener, who hears a drop in pitch.- Long Wavelength -Low Frequency

As the car comes closer, sound wave fronts reach a listener ever more quickly and seem to rise in pitch. Small Wavelength- High Frequency.

Doppler effect

Tuning Fork

When we strike a tuning fork, it will vibrate in a fixed frequency and a particular sound will be heard.

Tuning Fork

Sound waves produced by a tuning fork.

Acoustics of Auditorium

The clearest speech is heard in an auditorium when there is a time gap of 1/20^th of a second between the reflected rays and the direct rays, otherwise they will overlap and no sound can be heard clearly.

Acoustics of Auditorium

TEST YOURSELF

Spectrometer, Physics Practical for Standard 12

2011-01-30T09:33:00.000+05:30

Spectrometer
AIM : -
To determine the prism-angle of a given prism.
(Keeping prism-table steady)
APPARATUS :-
A spectrometer, a source of light, a prism, a sprit-level and a magnifying glass.

Spectrometer

Spectrometer Fixed Table

Spectrometr on left

Spectrometr on Right

Observations:

Spectrometer Observation table

Angle of prism

From the observations of window-X,

2A = q₁ - q₂

\A =

From the observations of window-Y,

2A = q_1’ - q_2’

\A =

It measures the color change. That gives the indication of the rate of the light reactions of the photosynthesis in the conditions of the experiment.

Spectroscopy is the study of the interaction between matter and radiated energy. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, e.g., by a prism. Later the concept was expanded greatly to comprise any interaction with radiative energy as a function of its wavelength or frequency. Spectroscopic data is often represented by a spectrum, a plot of the response of interest as a function of wavelength or frequency.

Spectrometry and spectrography are terms used to refer to the measurement of radiation intensity as a function of wavelength and are often used to describe experimental spectroscopic methods. Spectral measurement devices are referred to as spectrometers, spectrophotometers, spectrographs or spectral analyzers.

Daily observations of color can be related to spectroscopy. Neon lighting is a direct application of atomic spectroscopy. Neon and other noble gases have characteristic emission colors, and neon lamps use electricity to excite these emissions. Inks, dyes and paints include chemical compounds selected for their spectral characteristics in order to generate specific colors and hues. A commonly encountered molecular spectrum is that of nitrogen dioxide. Gaseous nitrogen dioxide has a characteristic red absorption feature, and this gives air polluted with nitrogen dioxide a reddish brown color. Rayleigh scattering is a spectroscopic scattering phenomenon that accounts for the color of the sky.

Spectroscopic studies were central to the development of quantum mechanics and included Max Planck's explanation of blackbody radiation, Albert Einstein's explanation of the photoelectric effect and Niels Bohr's explanation of atomic structure and spectra. Spectroscopy is used in physical and analytical chemistry because atoms and molecules have unique spectra. These spectra can be interpreted to derive information about the atoms and molecules, and they can also be used to detect, identify and quantify chemicals. Spectroscopy is also used in astronomy and remote sensing. Most research telescopes have spectrographs. The measured spectra are used to determine the chemical composition and physical properties of astronomical objects (such as their temperature and velocity).

Rate of Flow of Water,Physics practical For Standard 12

2011-01-27T14:59:00.000+05:30

RATE OF FLOW OF WATER
AIM :-
Fill water in a cylinder vessel, connected with a capillary, upto some height ho. Allow water to flow through capillary in a controlled way and measure the height (h) of water, in vessel, at regular intervals (t) of time. Take ten such observations. Draw a graph of h / t and find the half-life of the flow of water.

Apparatus : A burette
A stand
A beaker
A stop-watch
A capillary of fine bore
A rubber tube
A pinch cock
Water

Rate of Flow of Water

Rate of Flow of water

Observation table

Rate of Flow of water Observation table

Graph of Rate of Flow of Water

Rate of Flow of Water Observation table

Graph of Rate of Flow of Water

A Simple Pendulum for standard 12 physics

2011-01-26T19:01:00.000+05:30

A SIMPLE PENDULUM

AIM :-
To determine the value of g with the help of a simple pendulum.

PRECAUTIONS:
Understand clearly the functioning of the stop-clock.
The bob of the pendulum should not be given angular displacement more than 40.
The oscillations of the pendulum should be in one vertical plane only.
During oscillations the bob should not spin.
See that the bob does not collide with the table while oscillating.
The experiment should be performed at such a place where air current is slow. (Do not do the experiment near the window or a moving fan.)

APPARATUS : - A stand with a clamp,
                             a metallic bob,
                             a light string,
                             a meter rule,
                             a rubber cork with two pieces,
                             a vernier calliper
                             a stop-clock

Simple Pendulum Apparatus

Simple Pendulum

OBSERVATION TABLE

Simple pendulum observation table

Graph


Graph for Simple pendulum

Simple pendulum Presentation

Sonometer for standard 12 Physics Practical

2011-01-26T17:48:00.000+05:30

Sonometer

AIM :-
To study the relation between frequency and the length of a stretched string with the help of a sonometer.

PRECAUTIONS :-
The wire should be of uniform cross-section and there should not be any twist or bend in it.
The pulley should rotate without friction.
Put that much weight in the pan so that the deformation produced in the wire should not exceed the elastic limit.
The stem of the tuning fork, not its prongs, should be placed on the sonometer box or on the support.

Apparatus:-    A sonometer,
                       tuning forks ( of frequencies from 256 Hz – 512 Hz),
                       a pan or a hanger of known weight,
                       four to five 500 gm weights,
                        a paper rider,
                       a rubber-pad and
                       a meter rule.

Sonometer

OBSERVATION TABLE

Sonometer Observation table

Graph:-

Graph of Sonometer

Sonometer Presentation

Frequency of Aelternating Current For Standard 12 Physics

2011-01-26T17:10:00.000+05:30

Frequency of A.C.

AIM :-

To find the frequency of the alternating current with the help of a sonometer.

Sonometer Aim

PRECAUTIONS :-

It is not advisable to use sonometer wire made of iron or any other magnetic materials.

The measurement of radius of the wire should be carried out precisely.

The transformer key should be switched off after every observation.

The wire should be kept exactly in the middle between the magnetic poles.

The wire should be of uniform cross-section and it should not have a twist or a bend.

Sonometer Precaution

Apparatus :- A sonometer,

horse-shoe magnet,

a transformer,

a pan,

weights and

a micrometer screw.

Sonometer Apparatus

Sonometer Wiring diagaram

OBSERVATION TABLE

Sonometer Observation Table

Calculation:-

The linear density (i.e. mass per unit length) of the wire, m= prrr = .

Calculation of √T/L.

The frequency of alternating current f = 1 / 2L √T / m = 1 / 2 √m * (average √T/L )

Sonometer

(Frequency of Aulternating Current)

Presentation

Practical for standard 12

2011-01-25T18:34:00.000+05:30

Dear Friends
In Old Version in Physics Practical there is 19 Physics practical.
which all practical i am going to upload for quick understanding about practical.
I am making this blog for standard 12 which is under uploading more practical so be with me you will get practical presentation download free.

Resonance tube Practical for Standard 12

2011-01-25T17:17:00.000+05:30

RESONANCE TUBE Pr-19

AIM :-
To compare the frequencies of two tuning forks using a resonance tube and to find the end-correction. Repeat the experiment for two other tuning forks .
Find the lengths (l) of the resonating air columns for tuning forks of five different frequencies.
Draw a graph of 1 / f --

APPARATUS :-
A metallic tube open at both the ends (known as resonance tube),
a cylinder( of glass or metal) for filling water, a stand,
a meter rule,
a rubber-pad and tuning forks( two of known frequencies and two of unknown frequencies).

Apparatus for Resonance Tube

Resonance Tube Practical

OBSERVATION TABLE :-

(1) Least count of the vernier callipers = cm
(2) Internal diameter of the resonance tube : d1 = cm; d2 = cm
Average diameter d = cm

Observation table-1

(1) f1 / f2 = l2 / l1
(2) f3 / f4 = l4 / l3

Observation table-2

Resonance Tube Graph

Resonance tube Presentation

Measurement of Resistance (Wheatstone's Bridge)

2011-01-24T22:41:00.000+05:30

Practicle – 2
MEASUREMENT OF RESISTANCE ( WHEATSTONE’S BRIDGE)

AIM :-

You are given a Wheatstone bridge and other necessary instruments. Find the values of the unknown resistance Rx. Exchange the positions of unknown resistance and resistance box in the gaps of Wheatstone bridge and repeat the experiment.

PRINCIPLE :-

It works on the principle of balanced Wheatstone bridge.

APPARATUS:-

Wheatstone-bridge (meter-bridge),

2 Volt Battery,

Rheostat,

Galvanometer,

Jockey,

Key,

Resistance box(1 – 100 W),

Resistance coil.


Apparatus for Wheatstone's Bridge Practicle

Precautions :-

Make proper and tight connections.
Keep the keys tightly closed in the resistance box.
Adjust the value of resistance box so that null point is obtained between 40 cm and 60 cm.
Do not slide the jokey continuously over the wire.

Note :- Keep high resistance of rheostat in the beginning of each observation so that current is less and the galvanometer is not damaged. After getting approximate position of null point only decrease the resistance of rheostat.

(1) Condition :- Connect unknown resistance Rx between M – N.


Line Diagram For Wheatstone's Bridge

Wiring Diagram for Wheatstone’s Bridge.
Use this setup for carry out practical so it may be easy to understand.


Wiring Diagram for Wheatstone's Bridge

Measure L1 and L2 and note down in your Table.

(2) Condition :- Interchange unknown resistance Rx between P – Q.

In which interchange

Unknown Resistance RX and Known Resistance Box RB.

Line Diagram for Interchange RX And RB

Wiring Diagram for Wheatstone’s Bridge. (Condition-2)

In which interchange Unknown Resistance RX and Known Resistance Box RB.
Use this setup for carry out practical so it may be easy to understand.

Wiring Diagram for Interchange RX And RB

Conclusion :-

(1) Unknown Resistance, Rx = …….. W

(2) Unknown Resistance, Ry = ……...W

Law of Combinationof Resistors. (Wheatstone's Bridge),Video for std 8 to 12

2011-01-24T21:53:00.000+05:30

Practical - 3

LAWS OF COMBINATION OF RESISTORS

( WHEATSTONE’S BRIDGE & POST OFFICE BOX )

AIM :-

You are given a Wheatstone Bridge and other necessary instruments. Find the values of the unknown resistance Rx and Ry . Now connect them in series and parallel respectively and measure their resultant resistances and test the laws of series and parallel connections.

PRINCIPLE :- It works on the principle of a balanced Wheatstone bridge.

Apparatus :- Wheatstone-bridge (meter-bridge),

                         2 Volt Battery,
                         Rheostat,
                        Galvanometer,
                        Jockey,
                        Key,
                        Resistance box(1 – 100 W),
                        Resistance coil.

Wheatstone Bridge Apparatus

(1) Condition :- Connect unknown resistance R_x between M – N.

Wheatstone Bridge line Diagram (Condition-1)

Wheatstone Bridge Wiring Diagram (Condition-1)

(2) Condition :- Connect unknown resistance R_y between M – N.

Wheatstone Bridge line Diagram (Condition-2)

Wheatstone Bridge Wiring Diagram (Condition-2)

(3) Condition :- Connect unknown resistance in Series

Wheatstone Bridge line Diagram (Series connection)

Wheatstone Bridge Wiring Diagram (Series connection)

(4) Condition :- Connect unknown resistance in Parallel .

Wheatstone Bridge line Diagram (Parallel connection)

Wheatstone Bridge Wiring Diagram (Parallel connection)

OBSERVATION TABLE

Wheatstone Bridge Observation table

CALCULATIONS :-

(1 (1) Series connection, R’s = Rx + Ry + …..W

(2) Parallel connection, R’p = Rx Ry / Rx + Ry = ….W.

RESULT:-

(1) Unknown resistance, Rx = ….W, Ry = ….W

Wheatstone Bridge Observation table

CONCLUSION :

It is possible to verify the rules for series and parallel connections with the help of a meter bridge.

Precautions:-

(1) Make all connections tight.

(2) Clean the ends of the connecting wire with a sand paper.

(3) Plug keys of resistance box should be very tight.

(4) Adjust the value of R from the resistance box such that null-point is obtained between 40 cm. and 60 cm.