SCHOOL NAME SCHOOL NAME SCHOOL NAME Of Magnetic Moments... · has carried out his work for the investigatory project entitled _____ under my guidance and supervision. ... in earth’s

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www.ammhu.com A categorized blogging website and an Online Resource Centre For CBSE, RBSE, and Other State Boards — Raj Kumar Parashari, Head Science @ JPHS, Jaipur-302021

SCHOOL NAME SCHOOL NAME SCHOOL NAME

ADDRESS WITH PINCODE AND PHONE NUMBER

Submitted by Guided by

Student Name [ ]

Class With Section Teacher Name

Class Roll No. Designation

Board Roll No.

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INDEX

1. CERTIFICATE

2. ACKNOWLEDGEMENT

3. AIM

4. APPARATUS REQUIRED

5. PRINCIPLE / THEORY

6. RAY DIAGRAMS & IMAGES

7. PROCEDURE

8. OBSERVATIONS

9. CALCULATIONS

10. RESULT

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CERTIFICATE

This is to certify that _______________________

student of ______ school name _______, class XII Sc __

has carried out his work for the investigatory project

entitled _______________________________________

under my guidance and supervision.

Signature of the Teacher

Designation

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ACKNOWLEDGEMENT I __________________________________ a student of

____________________________________,______________

would like to pay my sincere gratitude to my Physics teacher

Mr. __________________________ for helping and guiding

me throughout the completion of the project report. I would

like to thank Mr./Mrs. _______________________ our school

principal/Director for making school such a wonderful place of

learning. I also would like to thank Mr. ________________

our lab assistant foe the timely assistant in completion of the

project.

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AIM To compare the magnetic moments of given two bar magnets

of unequal in size and mass.

APPARATUS REQUIRED A vibration magnetometer, two bar magnets (whose magnetic

moment is to be compared) and one additional magnet to initiate

the vibrations.

THEORY (a) Principle:—

It is used for the comparison of magnetic moments and

magnetic fields. The device works on the principle that

wherever, a freely suspended magnet in a uniform magnetic

field, is allowed to oscillate about its equilibrium position, its

starts vibrations about the mean position.

The time period of oscillation of experimental bar magnet

(Magnetic moment M) in earth’s magnetic field (BH) is given by

the formula

H

IT 2

MB

where, I = moment of inertia of short bar magnetic

/ 2 2M L B

I12

, here M/ = mass of the bar magnet.

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(b) Construction:—

It consists of a rectangular wooden box having glass walls at the

side and at the tap.

Three of the walls are fixed and the fourth may be slider in and

out. This is used to close or open the box. A plane mirror is

fixed on the mirror surface of the bottom of the box. A line

parallel to the length of the box in drawn on the mirror in the

middle, it is known as surface line. There are leveling screw at

the bottom an which the box rests.

A vertical cylindrical glass tube T, having a torsion head H, at

its top plate of the box A hanger is suspended in the box through

an unspun silk thread.

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(c) Use Of Vibration Magnetometer

(i)For the determination of magnetic moment of a bar

magnet.

The experimental magnet is placed inside the vibration

magnetometer and its time period T is determined.

Now H

IT 2

MB

2

2

H

4 IM

B T

(ii) Comparison of magnetic moments of two bar magnets of

same size and mass.

The time period of oscillation of experimental bar magnet

(Magnetic moment M) in earth’s magnetic field (BH) is given by

H

IT 2

MB

Here I and BH are constant, so 2

1 2

2

2 1

M T

M T

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(ii) Comparison of magnetic moments of two bar magnets of

unequal size and masses (by sum and difference method):

In this method both the magnets vibrate together in two

following positions

Sum position

Two magnets are placed such that their magnetic moments are

additive.

Net magnetic moment MS = M1 + M2

Net moment of inertia IS = I1 + I2.

The time period of oscillations of this pair in earth’s magnetic

field.

(BH)

S 1 2

S

S S 1 2 H

I I IT 2 2 ..............(i)

M B M M B

Difference position

Magnetic moment will be subtractive.

Net magnetic Moment MD = M1 – M2

Net moment of inertia Id = I1 + I2.

The time period of oscillations of the pair in earth’s magnetic

field (BH);

D 1 2

D

D D 1 2 H

I I IT 2 2 ..............(ii)

M B M M B

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From equation (i) and (ii)

2 2

S D S1 2 1

2 2

d 1 2 2 D S

T T TM M M

T M M M T T

PROCEDURE

(i) To start with, the instrument is made horizontal with the help

of a spirit level and the leveling screw.

(ii) A compass needle is placed on the reference line and the box

is rotated to make the reference line is parallel to the needle. The

reference line is now in magnetic meridian.

(iii) A needle is removed and a non magnet heavy piece is put

on the hanger. It oscillates for a while and finally stays in

equilibrium. Now with the help of torsion head at the top, the

bar is made parallel to the reference line.

(iv) The magnet is how gently placed in the hanger removing the

heavy piece. The magnet is set into angular oscillations about

the thread as axis. This may be done by bringing another magnet

close to the box and then removing it.

(v) The time period of oscillation is obtained by observing the

time period for, say 5 oscillations.

(vi) To measure time period accurately, one should look at the

magnet oscillations through the top glass – cover of the box. The

eye should be positioned in such a way that the image of the

magnet in the bottom mirror should be just below the magnet.

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(vii) Oscillations are counted as the magnet crosses the reference

line. The box is kept closed all the time of oscillations, so that

air current do not disturb the oscillations.

Observations:—

For Two Magnets with M1+ M2

S.NO. Time For 5 Oscillations t in sec

Time Period T = (t/5) sec

1. 2. 3. Mean Time Period TS =

For Two Magnets with M1– M2

S.NO. Time For 5 Oscillations t in sec

Time Period T = (t/5) sec

1. 2. 3. Mean Time Period TD =

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Calculations:—

The ratio of Magnetic Moment of unequal size and same mass

22 2

1

2 2

2

...........

...........

D S

D S

T TM

M T T

=

Result:—

The ratio of magnetic moments of the two magnets is …….

PRECATUIONS AND SOURCES OF ERRORS

1. To measure the time period accurately one should look at

the magnet through the glass cover of the box.

2. The eye should be positioned in a way that is image of the

magnet in the bottom mirror should be just below the magnet.

3. The box is just closed at the time of oscillation, so that air

current does not disturb the oscillation.

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Bibliography

1. H.C. Verma

2. University Physics

Note: — Hand written Investigatory Project

Report should be submitted. Work should be

neat and clean. Avoid unnecessary fancy

decoration of the project report.

Note: — Learn theory, working and related

viva for board practical examination.

Wish you all the best.

Raj Kumar Parashari

Head Science

JPHS, Jaipur

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SCHOOL NAME SCHOOL NAME SCHOOL NAME Of Magnetic Moments... · has carried out his work for the investigatory project entitled _____ under my guidance and supervision. ... in earth’s