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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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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
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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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
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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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
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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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
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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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
(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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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
(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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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
(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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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
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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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
(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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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
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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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
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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