KENDRIYA VIDYALAYA NO.2 INDORE

Electromagnetic Induction

ELECTROMAGNETIC

INDUCTION

PHYSICS INVESTIGATORY

PROJECT

SUBMITTED BY

BHUVNESH TENGURIA

Under the guidance of

Mr. MUKESH BAGDI

KENDRIYA VIDYALAYA NO 2

INDORE M.P.

KENDRIYA VIDYALAYA (NO 2)

INDORE M.P.

PHYSICS

2014-2015

BONA FIDE CERTIFICATE

This is to certify that this project entitled “Electromagnetic

Induction” is a record of bona fide work carried out

by Bhuvnesh Tenguria in Physics prescribed by Kendriya

Vidyalaya No 2 INDORE M.P.

ROLL NUMBER: DATE:

INTERNAL EXAMINER : PRINCIPAL: EXTERNAL EXAMINER :

DECLARATION

I hereby declare that the project work entitled

“Electromagnetic Induction” submitted to KENDRIYA VIDYALAYA NO.2,

INDORE for the subject Physics under the guidance of Mr. M BAGDI

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.S.P Bhatt Principal,

Kendriya Vidyalaya (No.2) Indore, 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 Mr. M Bagdi (PGT PHYSICS) for his 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 /Bibliography

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 (b) Cross-sectional view inside a solenoid

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.

Electromagnetic Induction

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 (Ø or ØB) 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 CGS 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

ØB= B.S = BScosθ

Where B 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.

dØB= B.dS

From the magnetic vector potential and the fundamental

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

ØB= ∮δs

A.dl

where the line integral is taken over the boundary of the surface, which is denoted as δS .

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 (Ø ) 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,

F=q(E+v×B)

And the EMF of the wire loop is

ε = ∮ (1/q)F.dl ε = ∮ (E+v×B).dl

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

∇ × E= -(δB/δt)

Where is the curl operatoe and againE(r,t) is the electric field and B(r,t) 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