electromagnetic induction & useful applications

Electromagnetic Induction & Its Applications

PHY123 PresentationGroup: ASTUTE

• Tasnuva Tabassum Oshin: 151-15-4673• Masumer Rahman: 151-15-5040• Mariya Rahman: 151-15-5317• T.M Ashikur Rahman: 151-15-4971• Soummo Suprya: 151-15-4741• Md. Fazle Rabbi Ador: 151-15-5482

introductionHistory of Electromagnetic Induction.

What is Electromagnetic Induction?

Requirements of Electromagnetic induction

Amount of Induced e.m.f.

Faraday’s Law of Electromagnetic Induction

Direction of Induced emf and CurrentLenz’s Law

Direction of Induced emf and CurrentFleming’s Right Hand Rule

Useful applications

• Soummo Supriya151-15-4741

History of Electromagnetic Induction

*Almost 200 years ago, Faraday looked for evidence that a magnetic field would induce an electric current with this apparatus.

*He found no evidence when the magnet was steady, but did see a current induced when the magnet moves up and down .

Faraday learned that if you change any part of the flux over time you could induce a current in a conductor and thus create a source of EMF (voltage, potential difference).

History of Electromagnetic Induction

What is Electromagnetic Induction?

When the Magnetic flux linking with a conductor or coil and changes an e.m.f. is induced in the conductor. If the conductor

forms a complete loop or circuit, a current will flow in it, that’s called the Electromagnetic Induction.

• T.M. Ashikur Rahman

151-15-4971

Requirements of Electromagnetic induction

1) The first and basic requirement for electromagnetic induction is the change in Flux linking with the conductor (or coil).2) The e.m.f. and hence the current in this conductor (or coil) will persist so long as this change is taking place.3)The requirement is not only linking the coil with the Flux, the main thing is, if we want to induced some e.m.f. The Flux should be change after linking with coil.

Amount of Induced e.m.f:

The amount of induced e.m.f. in a coil is directly proportional to---- 1) the number of turn on the coil,

2) the rate change the Flux linking with coil.

Amount of Induced e.m.f:

tNN

tN

eortheChangTimeTakenfuxChangeofFlN

geofFluxrateofChanN

12

)12(

Induced emf is

Here,N= Number of Turn of Coil= the change of Flux linking by conductort= time of changing the flux

• Masumer Rahman 151-15-5040

Faraday’s Law of Electromagnetic Induction:-

Faraday performed a series of experiments to the phenomenon of

electromagnetic induction. He performed two laws about electromagnetic induction

a known as Faraday’s law:-


First Law:“When the Changes Flux linking with a conductor or coil, an emf is Induced in it.”


Second Law:“The magnitude of induced emf in a coil is directly proportional to the rate of change of flux linkages”

Mariya Rahman151-15-5317

The direction of Induced emf and hence current in conductor or coil can be determined by one of the following methods:

1. Lenz’s Law2. Fleming’s Right hand Rule.

Direction of Induced e.m.f and CurrentLenz’s Law

1) Lenz’s Law:- Email Lenz, observed that the direction of induced emf has a defined relation to change of magnetic field that produces it. He gave the simple following simple rule:-

“An Induced Current will flow in such a Direction

so as to oppose the cause that produces it.”


• The cause that the change of produces current is the change of flux linking the coil. Therefore, the direction of induced current will be such that its own magnetic field oppose the change in flux that produced the induced current.

• That means the induced current on its conductor or coil will be the oppose direction of the original flux direction.


We know that, the magnetic flux always flow through from North pole to South pole. So, Current will be flow through from South to North.


Tasnuva Tabassum Oshin151-15-4673


• This is the Rule of particularly suitable to find the direction of Induced emf and hence current when the conductor moves at right angles to a stationary magnetic field.

• Stretch out the Four finger, Middle finer and thumb of Your right hand so that they are at right angles to one another.


“If the forefinger points to direction of the magnetic field, Thumb is the direction of motion the conductor, then the middle finger will point in the direction to the Induced Current.”


Consider that, A Conductor is Moving as the direction of Forefinger, the magnetic flux is go through from the north to south pole as the same direction of Thumb finger, now Current will be flow as the same direction of the middle finger.

Md. Fazle Rabbi Ador

151-15-5482

Useful applications

AC GeneratorAC Generators use

Faraday’s law to produce rotation and thus

convert electrical and magnetic energy into

rotational kinetic energy. This idea can be used to run all kinds of motors.

Electro magnetic induction can

create an electrical motor by passing a current through a

set of electro-magnets mounted on a rotating shaft.

ELECTRIC MOTOR

MAGNETIC RECORDS

Write data by magnetizing recording media (e.g., video tape, hard disk) using electromagnets.Data is read back using the induced current produced when magnetized media moves past receiver coils (reverse of writing data).

ELECTRIC STOVES

The water in the metal pot is boiling. Yet, the water in the glass pot is not boiling, and the stove top is cool to the

touch. The stove operates in this way by using

electromagnetic induction.

MAGNETIC BRAKES

Great America’s Drop Zone has a 22

story free fall, lasting four

seconds, decelerated by

magnetic braking.

ANY QUESTION???

electromagnetic induction & useful applications

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