TOPIC

ELECTROMAGNETIC
INTRODUCTION
 AIM

To study the phenomenon of

Electromagnetic Induction
 INTRODUCTION

Electro Magnet
An electromagnet is a type of magnet in which the
magnetic field is produced by electric current. The
magnetic field disappers When the current is
turned off.

INDUCTION
This process of generating current in a conductor
by placing the conductor in a changing magnetic
field is called Induction.

Electromahnetic induction:
Electromagnetic induction is the production of a
potential difference (voltage) across a conductor
when it is exposed to a varying magnetic field.
Electromagnetic induction is when an
electromagnetic field causes molecules in another
object to flow. Induction can produce electricity (in
coils),heat (in ferrous metals), or waves (in a radio
transmitter).
Finally, it is referring to the phenomenon where an
emf is induced when the magnetic flux linking a
conductor change.
Magnetic Flux is defined as the product of the
magnetic flux density and the area normal to the
filed through which the field is passing. It is a
scalar quantity and its S.I. unit is the weber.

PRINCIPAL:
Electromagnetic induction (or sometimes just
induction) is a process where a conductor placed
in a changing magnetic field(or a conductor
moving through a stationary magnetic field)
causes the production of voltage across the
conductor. This process of electromagnetic
induction, in turn causes an electrical current –it is
said to induce the current
 THEORY

INVENSION:
Michael faraday is genrally credited with the
discovery of induction in 1831 through it may have
been anticipated by the work of francesco
Zantedeschi in 1829. Around 1830 to 1832,Joseph
henry made a similar discovery, but did not publish
his findings until later.

Induced e.m.f:
If magnetic flux through a coil is altered then an
e.m.f. will be genrated in the coil. This effect was
first obsever and explained by Ampere and faraday
between 1825 and 1831. Faraday discovered that
an e.m.f. could be genrated either by ,
(a) Moving the coil or the source of flux relative
 to each other or
(b) By changing the magnitude of the source of
magnetic flux
Note that the e.m.f. is only produced while the
flux is changing.

For example, consider two coils as shown

Current is produced in a conductor when it moved

through a magnetic field because the magnetic
lines of force are applying a force on the free
elecyrons in the conductor and cusing them to
move. This process of genrating current in a
conduct by placng conductor in a changing field is
called induction. This called induction because
there is no physical connection between the
conductor and magnet. This current is ssaid to be
induced in the conductor by the magnetic field.
One requirement for this electromagnetic
induction to take place is that the conductor, which
is often a pieac of wire, must be perpendicular to
the magnet lines of force in order to produce the
maximum force on the free electrons. The
direction that the induced current flow is
detrmined by the direction of lines of force of
direction the wire is moving in the field. In the
picture above the ammeter (the instrument used
to measure the current)indicates when there is
current in the conductor.

Lenz’s Law:
Whe an e.m.f. is genrated by a change in magnetic
flux according to faraday’s Law, the polarity of the
induced e.m.f. s shuch that is produces a current
whose magnetic field oppose the change which
produces it. The induced magnetic field inside any
loop of wire always acts to keep the magnetic flux
in the loop constant.in the examples bellow, if the
B field is incresing , the induced field acts in
opposition to it. If it is decresing, induced field acts
in the direction of the applied field to try to keep it
constant.

Applications of electromagnetic
induction

Electrical generator
The e.m.f. generated by faraday’s law of induction
due to relative movment of circuit and a magnetic
field is the phenomenon underlying electrical
gentrators. When a permenent magnet is moved
relative to a conductor’ or vise versa, an
electromotive force is created. If the wire is
connected through electrical load, current will flow,
thus electric energy is genrated, converting the
mechanical energy of motion to electric energy.

Electrical trnsformar:
The e.m.f. predicted by faraday’s law is also
resposibale for electrical transformars. When the
electric current in a llop of wire changes, the
changing current creates a changing magnetic
field.a second wire in reach of the magnetic field
will experience this change in magnetic field as a
change in this magnetic flux, d /dt. Therefore, an
electromotive force is set up in the second loop
called the induced e.m.f. transformer e.m.f.. if the
two ends of loopare connected through an
electrical load, current will flow.

OBSERVATION
: Magnet is moved at certain rate and certain
voltage is produced.

: Magnet is moved at faster rate and creating a

greater induced voltage.

: Magnet is moved at same speed through coil

that has greater number of turn and greater
voltage d induced.
 CONCLUSION
Faraday’s law of electromagnetic induction, first
obseved and pubished by michael faraday in the
mid-nineteenth century, discribes a very important
electro-magnetic 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 field. This concept has very farreaching
ramification that touch our lives in many ways:
from the shing of the sun, to the convenience of
mobile communications, to electricity to power our
homes. We can all appreciate the profound impact
faraday’s has on us.
 APPLICATION OF
ELECTROMAGNETIC INDUCTION IN
REAL LIFE

The principles of electromagnetic induction is

applied in many devices and systems, inculding:
1) Electrical genrators
2) Induction motors
 3) Induction sealing
4) inductive charging
5) Transformars
6) Wireless energy transfer
7) Wireless charger

PRECATIONS
1) Do all the connection carefully

2) Do not scratch insulated copper wire

while making loop

3) Do not use digital voltmeter for above

demostration

4) Do not use very thin copper wire

5) Use only insulated copper wire

6) Keep your self safe from high voltage

7) Before doing any experiment consult to
your subject teacher or lab assistance