PHYSICS INVESTIGATORY REPORT ON
EARTH MAGNETIC FIELD’S MAGNETIC FIELD
USING TANGENT GALVANOMETER
NAME
: ARSHAD.S
CLASS
: XII C
ROLL NO:
SSVM WORLD SCHOOL
Department of Chemistry
Bonafide Certificate
I hereby certify that this project entitled STUDY OF CASEIN
PRESENT IN MILK bonafide work done by ARSHAD.S
Register No: __________________
In the department of Physics of SSVM WORLD SCHOOL under my
supervision during the academic year 2022-2023 .
Date:____________________________
Signature of teacher in charge
Signature of the Principal
Submitted for practical examination held in the school centre
on_______________________
Internal Examiner
School seal
External Examiner
ACKNOWLEDGEMENT
The successful completion of any task would be incomplete without mentioning
the names of those people who helped to make it possible. I owe my due reverence
to the CBSE board for including practical work as a part of our curriculum and to
my school, SSVM World School for giving us the opportunity and resources to
complete this project effectively.
I take this opportunity to express my gratitude and respect in few words to all
those who helped me in the completion of this project. I would like to express my
special thanks to our Correspondent Madam, Principal Mrs. Nimitha Pramod and
the teachers of Computer Science department Mr. Rajendran and Mrs. Shivagami
who gave me the required help and support to do this project on this topic. This
project helped me in doing a lot of research and learning new things. Secondly I
would like to thank CBSE for giving me such an opportunity without which I
would not have been able to do such a project. I would also like to thank my
parents and friends who helped me a lot in finalizing this project within the
limited time frame. Above all, I thank God for showering his plentiful blessing in
keeping us safe all year through and enabling us to work without any obstacles.
INDEX
Sno:
CONTENTS
Pg. NO:
1
INTRODUCTION
1
2
OVERVIEW
2
3
AIM
3
4
PRINCIPLE
4
5
THEORY
6
6
DIAGRAM
8
7
RESULT
9
8
BIBLIOGRAPHY
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INTRODUCTION
Ancient explorers made extensive use of the earth's magnetic field to explore the
planet, but they were unaware of its origin. The features of the earth's magnetic
field resemble those of a bar magnet in many ways, yet the processes that produce
them are very different.
It appears that magnetic field lines begin close to the south geographic pole, also
known as the magnetic north pole, and end close to the north geographic pole,
also known as the magnetic south pole. It's noteworthy to note that the magnetic
field lines enter the earth at a relatively sharp angle close to Wilmington, North
Carolina.
A compass needle's angle of inclination, also known as its dip angle, is roughly
equal to its angle with regard to the plane of the horizon 60. In this experiment,
the earth's magnetic field at Wilmington, North Carolina, is determined using the
fundamentals of vector analysis and magnetostatics.
An early measuring device for calculating electric current was the tangent
galvanometer. It operates by comparing the magnetic field produced by the
unknown current to the magnetic field of the Earth using a compass needle. The
tangent law of magnetism, which is its guiding principle, asserts that the angle a
compass needle makes is proportionate to the ratio of the strengths of the two
perpendicular magnetic fields. This law gives compass needles their
characteristic tangent angle. Claude Pouillet initially described it in 1837.
1
OVERVIEW
An early measuring device for calculating electric current was tangent
galvanometer. It operates by comparing the magnetic field produced by the
unknown current to the magnetic field of the Earth using a compass needle. The
tangent law of magnetism, which is its guiding principle, asserts that the angle a
compass needle makes is proportionate to the ratio of the strengths of the two
perpendicular magnetic fields. This law gives compass needles their
characteristic tangent angle. Claude Pouillet initially described it in 1837. Who
subsequently used this delicate type of galvanometer to confirm Ohm's law.
The coil's magnetic field has a magnitude of B, while the Earth's magnetic field's
horizontal component has a magnitude of B'. The compass needle rotates via an
angle from its initial orientation and then aligns itself with the vector sum of B
and B'. Tan is equal to B/B', as shown by the vector figure. The current is therefore
proportional to the tangent of the angle across which the needle has turned
because the magnetic field of the Earth is constant and B depends directly on the
current.
2
AIM OF THE PROJECT
The project's goal is to determine the horizontal component of Earth's magnetic
field and the "reduction factor" of the specified tangent galvanometer (K) (Bh).
● To establish the provided tangent galvanometer's reduction factor (K).
● To identify the earth's magnetic field's horizontal component (Bh).
APPARATUS AND MATERIALS REQUIRED
> Tangent galvanometer (TG)
> Commutator ©
> Rheostat ®
> Battery (E)
> Ammeter (A)
> Key (k)
3
PRINCIPLE
The tangent galvanometer works on the principle of tangent law. The magnetic
needle is subjected to two magnetic fields which are perpendicular to each other.
One field is due to the horizontal component of the earth’s magnetic field and the
other is created by passing the current through the coil of the tangent
galvanometer. Under the action of two magnetic fields the needle comes to rest
making angle θ with BH, such that B = BH tan θ
WORKING
When the current is not passed through the coil the magnetic needle is acted upon
by only a horizontal component of the earth and thus the magnetic needle remains
in the north-south direction. When the current is passed through the coil a
magnetic field is created by the coil. Thus the magnetic needle is now acted upon
by two magnetic fields which are at a right angle to each other. Hence the needle
will turn through an angle say θ.
Let BH be the horizontal component of the earth’s magnetic induction and B be
the magnetic induction at the centre of the coil due to the current in the coil. The
direction of B will be perpendicular to the plane of the coil and hence
perpendicular to BH. By the tangent law
B = BH tan θ …………. (1)
The magnetic induction at the centre of the coil due to current in the coil is
given by
4
Where k is a constant, called the reduction factor of the tangent galvanometer.
∴ i ∝ tan θ
Thus in a tangent galvanometer, the current through the coil is directly
proportional to the tangent of the angle of deflection of the needle. Due to this
characteristic of the galvanometer is known as the tangent galvanometer.
Knowing k and θ we can calculate the value of the current through the coil.
5
THEORY
The tangent galvanometer works on the principle of tangent law. The magnetic
needle is subjected to two magnetic fields which are perpendicular to each
other. One field is due to the horizontal component of the earth’s magnetic field
and the other is created by passing the current through the coil of the tangent
galvanometer. Under the action of two magnetic fields the needle comes to rest
making angle θ with BH, such that B = BH tan θ
An ancient tool for measuring tiny electric currents was tangent galvanometer.
It is made up of an insulated coil of copper wire wound around a non-magnetic
frame. The tangent law of magnetism serves as the foundation for how it
operates. A magnetic field (B) is created at the center of the circular coil when a
current is run through it in a direction perpendicular to the coil's plane. The TG
is set up so that the coil's plane is parallel to the direction of the horizontal
component of the earth's magnetic field (Bh). The magnetic needle is then being
acted upon by two fields that are perpendicular to one another.
Let I is the current passing through the coil of radius a with n turns, then the
field generated by the current carrying circular coil is,
Equating (1) and (2), we get,
6
The left hand side of equation (4) is a constant and is called the reduction factor
(K) of the given tangent galvanometer.
PROCEDURE
In the diagram below, where K is the key, E is the battery, A is the ammeter, R is
the rheostat, C is the commutator, and T.G is the tangent galvanometer,
connections are made as described. Without altering the current in the rest of the
circuit, the commutator can switch the direction of current via the T.G coil. Any
slight misalignment of the TG coil with respect to the earth's magnetic field
averages out by taking the average of the two readings for deflection.
PROCEDURE FOR PERFORMING EXPERIMENT
● The leveling screws are adjusted to make the coil's plane vertical.
● The compass box is turned independently so that its 90-degree line is in the
coil's plane.
● The T.G is spun as a complete till the aluminum pointer displays 0-0.
● Record the coil's number of turns.
● The coil is allowed to receive a reasonable current.
● Record both the current and the deflection in the T.G.
● Switch the current around and observe the deflection once more.
● Repeat the process with various current values.
● Create a graph.
Using a thread and rotating it around the circular object, determine the coil's
radius from its circumference.
7
DIAGRAM
OBSERVATIONS AND GRAPH
Number of turns in the coil = Circumference
of the coil = 2πa
Radius (a) of the coil
=
TO DETERMINE THE REDUCING FACTOR OF T.G.
8
RESULT
The reduction factor of the given tangent galvanometer ,K =______________A
Horizontal component of Earth’s magnetic field , Bh = ____________T
APPLICATIONS
1.
T.G. can be used to measure the magnitude of the horizontal
component of the geomagnetic field.
2.
The principle can be used to compare the galvanometer constants.
9
BIBLIOGRAPHY
BOOKS:
● Physics For Class 12 NCERT
● New Simplified PHYSICS for class 12 by SL.ARORA
LINKS AND OTHER REFERENCES:
● https://wikipedia.com/
● https://youtube.com/
● https://slideshare.com/
● https://quillbot.com/
● https://www.sciencedirect.com/
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