KENDRIYA VIDYALAYA, NO.1, MADURAI

Electromagnetic Induction

ELECTROMAGNETIC

INDUCTION

PHYSICS INVESTIGATORY

PROJECT

SUBMITTED BY

Under the guidance of

MISS. I. SELVAMATHY

KENDRIYA VIDYALAYA NO 1, NARIMEDU, MADURAI-625002

KENDRIYA VIDYALAYA (NO 1)

NARIMEDU MADURAI-625002

PHYSICS

2013-2014

BONA FIDE CERTIFICATE

This is to certify that this project entitled “Electromagnetic

Induction” is a record of bona fide work carried out

by Vishnuprasad.V.P in Physics prescribed by Kendriya

Vidyalaya, Narimedu, Madurai -625002.

ROLL NUMBER: DATE:

INTERNAL EXAMINER : PRINCIPAL : EXTERNAL EXAMINER :

DECLARATION

I hereby declare that the project work entitled

“Electromagnetic Induction” submitted to KENDRIYA VIDYALAYA

NO.1, MADURAI for the subject Physics under the guidance of

MISS. I. SELVAMATHY is a record of original work done by me. I

further declare that this project or any part of it has not been

submitted elsewhere for any other class.

Class: Place: Date:

ACKNOWLEDGEMENT

First and foremost, I praise and thank the god almighty from the bottom

of my heart, who has been an unfailing source of strength, comfort and

inspiration in the completion of this project work.

I wish to express my sincere thanks to Mr.C.MUTHIAH

Principal, Kendriya Vidyalaya (No.1), Madurai, for the successful

outcome of this project work.

I wish to express my deep and profound sense of gratitude to my

teacher and guiding light MISS I SELVAMATHY (PGT PHYSICS) for her

expert and valuable guidance, comments and suggestions.

I also express my gratitude to my parents and friends who have helped

me in preparing this project.

TABLE OF CONTENTS

ᴥ Introduction

ᴥ Objective

ᴥ Apparatus required

ᴥ Theory

ᴥ Conclusion

ᴥ References

INTRODUCTION

Faraday’s Law of Electromagnetic Induction: It is a basic law of electromagnetism predicting how a magnetic field

will interact with an electric circuit to produce an electromotive force (EMF). It is the

fundamental operating principle of transformers, inductors and many types of

electrical motors and generators.

Faraday explained electromagnetic induction using the concept of lines of force.

These equations for electromagnetic induction are extremely important since they

provide a means to precisely describe how ,many natural physical phenomena in

our universe and behave.

Michael Faraday

The ability to quantitatively describe physical phenomena not only allows us to gain

a better understanding of our universe, but it also makes possible a host of

technological innovations that define modern society. Understanding Faraday’s

laws of electromagnetic induction can be beneficial since so many aspects of our

daily life function because of the principles behind Faraday’s law.

From natural phenomena, such as the light we receive from the sun, to

technologies that improve our quality of life, such as electric power generation,

Faraday’s law has a great impact on many aspects of our lives.

(a) Representation of magnetic fields

inside a solenoid

(b) Cross-sectional view

Electromagnetic Induction

Faraday’s law describes electromagnetic induction. Whereby an electric field is

induced, or generated by a changing magnetic field.

In Faraday’s first experimental demonstration of electromagnetic induction, he

wrapped two wires around opposite sides of an iron ring or ‘torus’ to induce

current.

Faraday’s law is a single equation describing two different phenomena: the

motional EMF generated by a magnetic force on a moving wire, and the

transformer EMF generated by an electric force due to a changing magnetic field.

EXPERIMENT

APPARATUS REQUIRED

Insulated Copper wire

An iron rod

A strong magnet

A light emitting Diode (LED)

OBJECTIVE

To determine the Faraday’s law of electromagnetic

induction using a copper wire wound over an iron rod and a strong

magnet.

THEORY

The magnetic flux ( or B) through a surface is the component of

the magnetic field passing through the surface.

The SI unit of magnetic flux is weber (Wb), and the COGS unit is

maxwell.

Representation of Magnetic flux ( ) in a

solenoid

Magnetic flux is usually measured with a flux meter, which contains

measuring coils and electronics that evaluate the change of voltage

in the measuring coils to calculate the magnetic flux.

If the magnetic field is constant, the magnetic flux passing through

a surface of vector area S is

B

Where is the magnitude of magnetic field having the unit of

Wb/m2(T). is the area of the surface and is the angle between

magnetic field lines and the normal.

For a varying magnetic field, we first consider the magnetic flux

through a small amount of area where we may consider the

magnetic field to be constant.

B

From the magnetic vector potential and the fundamental

theorem of the curl, the magnetic field may be defined as

B

where the line integral is taken over the boundary of the surface

, which is denoted as .

LAW

The most widespread version of Faraday’s law of electromagnetic

induction states that

“The induced electromotive force in any closed surface is equal to

the negative of the rate of change of magnetic flux through the

circuit.”

This version of Faraday’s law strictly holds true only when the

closed circuit is a loop of infinitely thin wire, and is invalid in other

circumstances as discussed below. A different version, the

Maxwell-Faraday equation is valid in all circumstances.

The magnetic flux ( ) changes due to the change in magnetic field.

Faraday’s law of electromagnetic induction states that the wire

loop acquires an EMF, defined as the energy available per unit

charge that travels once around the wire loop.

Equivalently, it is the voltage that would be measured by cutting

the wire to create an open circuit. And attaching a voltmeter to

the leads.

According to Lorentz force law,

X

And the EMF of the wire loop is

X

where (i) is the electric field

(ii) is the magnetic field

(iii) is the infinite length along the wire

And the line integral is evaluated along the wire.

The Maxwell-Faraday equation states that a time varying magnetic

field is always accompanied by spatially varying, non-conservative

electric field and vice versa. The Maxwell-Faraday equation is

X

where is the curl operatoe and again is the electric field

and is the magnetic field. These fields can generally be

functions of position and time .

The four Maxwell’s equations (including the Maxwell-Faraday

equation), along with the Lorentz force law are a sufficient

foundation to derive everything in classical electromagnetism.

Therefore, it is possible to “prove” Faraday’s law starting with

these equations. Faraday’s law could be taken as the starting point

and used to prove the Maxwell-Faraday equation and/or other

laws.

CONCLUSION

Faraday’s law of electromagnetic induction, first observed and

published by Michael Faraday in the mid-nineteenth century,

describes a very important electromagnetic concept. Although its

mathematical representations are cryptic, the essence of Faraday’s

law is not hard to grasp. It relates an induced electric potential or

voltage to a dynamic magnetic field. This concept has many far

reaching ramifications that touch our lives in many ways: from

shining of the sun to electricity and power in our homes. We can all

appreciate the profound impact Faraday’s law has on us.

REFERENCES

www.wikipedia.com

www.howstuffworks.com

www.scienceforall.com

www.100scienceprojects.com

Google images