Physics Project Reports on Electromagnetic Induction

Physics Project Reports on Electromagnetic Induction

Physics Project Report on Electromagnetic Induction

Physics Project Report on Electromagnetic Induction :

Electromagnetic Induction (EMI) : In 1831 Michael Faraday observed the impact known as “Electromagnetic Induction” just speak to the magnetic effect of electric cutting-edge.

When a coil product of copper twine is placed internal a magnetic field, magnetic flux is related with the coil. Faraday discovered that after the magnetic flux linked with the coil is modified, an electric modern begins flowing within the coil, furnished the coil is closed one. The contemporary and e.M.F. So produced are referred to as brought about modern and brought about e.M.F. The prompted current and the e.M.F. In the coil closing best so long as the magnetic flux linked with the coil maintains on changing.

Thus electromagnetic induction is the phenomenon of manufacturing of electric current (or e.M.F.) in a coil whilst the magnetic flux connected with the coil is modified.

Faraday’s Experiment

The following experiment executed via Faraday caused the discovery of the electromagnetic induction.

When the power of magnetic subject is various :

Consider coil P and S wound on an iron rod. Iron rod is hooked up with galvanometer, battery and tapping key. When tapping key’s pressed and when it is launched galvanometer suggests deflection showing the presence of prompted contemporary.

Explanation : When the tapping key is pressed then magnetic flux related with the coil S modified due to boom in magnetic field of coil P and brought about modern is produced and whilst it’s far launched magnetic flux is once more changed and caused contemporary is produced. But while the tapping secret is stored pressed then the magnetic flux related with coil do now not modified and induced contemporary do not produce so galvanometer shows no deflection.

Faraday’s Laws of Electromagnetic Induction :

The effects of Faraday’s test on electromagnetic induction are called “Faraday’s Law of Electromagnetic Induction”. These are stated as underneath :

1. Whenever magnetic flux related with a circuit (a loop of wire or a coil or an electric circuit in popular) modifications, prompted e.M.F. Is produced.

2. The triggered e.M.F. Lasts as long as the change in magnetic flux non-stop.

3. The importance of triggered e.M.F. Is at once proportional to the price of trade of magnetic flux related with the circuit.

Lenz’s Rule :

Lenz’s rule is a handy approach to decide the direction of precipitated present day produced in the circuit.

Lenz’s law states that the brought on cutting-edge produced in a circuit constantly flows in one of these path that it opposes the trade or reason that produce it.

Let us now apply Lenz’s regulation to find the route of go with the flow of prompted cutting-edge within the circuit.

On urgent the key the cutting-edge within the coil P flows in clockwise course and magnetic lines of pressure are directed from left to proper. Then magnetic flux connected with the coil S modified. The route of triggered cutting-edge must be such that it ought to oppose the direction of go with the flow of magnetic subject traces. So brought about contemporary in the coil S is inside the path contrary to the magnetic field in P. Hence, course of induced current in coil S is from right to left. So brought on present day in coil S need to drift in anticlockwise direction.

Expression for Motional e.M.F. :

Consider that a uniform magnetic subject B constrained to the area PQRS and a coil ABCD is positioned inside the magnetic field. The course of magnetic discipline is perpendicular to the plane of the coil and in inward direction.

Consider that at any time t, the element BA’ = CD’ = x(say) of the coil in the magnetic field. If l is the length of the arm BC of the coil, then area of coil inside the magnetic field at any time t.

A = BCX CD’ = lx

Therefore magnetic flux connected with the coil at any time t.

F = BA = Blx

Suppose that the coil is pulled out of the magnetic area with pace n. As the coil is pulled out magnetic flux linked with the coil modifications. The time rate of change of magnetic flux connected with the coil is given via

If e is precipitated e.M.F. Produced, then

e = -Bln

The poor sign indicates that precipitated e.M.F. Opposes to the coil being pulled out of magnetic field.

Mutual Induction :

Consider two coil P and S are located very near each other. Coil P consists of battery and tapping key and coil S includes galvanometer G. When the key of coil P is pressed then magnetic flux is constructing and induced e.M.F. Produced in it opposes the drift of magnetic flux. Because coil P and coil S are very near every other. So magnetic flux additionally modified in coil S and brought on contemporary is produced which opposes the path of drift of magnetic traces of pressure in coil P.

The phenomenon in step with which an opposing e.M.F. Is produced in a coil because of alternate in present day or magnetic flux related with a neighboring coil is referred to as mutual induction.

Coefficient of Mutual Induction :

Suppose that modern I is flowing through coil P and f be the magnetic flux related with coil S

f a I

f = MI

M = Coefficient of mutual induction.

Let e be the induced e.M.F. In coil S.

E = – (-ive signal suggests competition of brought about e.M.F.)

M = e /

The mutual inductance of two coils is stated to be one Henry, if a fee of change of modern-day of 1 ampere in step with 2d in one coil induces an e.M.F. Of 1 volt in neighboring coil.

Self Induction

Consider a coil connected to a battery and a tapping key. When key K is pressed magnetic strains of forces starts offevolved developing via it and brought about e.M.F. Is produced. Direction of prompted e.M.F. Is contrary to that of growth of modern-day. On the other hand when secret is released the contemporary in the coil decreases and e.M.F. Is produced in opposite route. Thus at some stage in both growth and decay of modern an opposite brought on e.M.F. Is produced. This e.M.F. Is referred to as back e.M.F.

The phenomenon in line with which an opposing brought about e.M.F. Is produced in the coil because of change in present day or magnetic flux related with the coil is referred to as self induction.

Coefficient of Self Induction :

Suppose whilst key is pressed, cutting-edge I flows thru the coil and magnetic flux f related with the coil.

F a I

f = MI

L is called coefficient of self induction.

Let e be the brought about e.M.F.

E =

e = (-ive sign suggests opposing nature of triggered e.M.F.)

M = e /

Self inductance of a coil is stated to be one Henry if a charge of trade of current of 1 ampere per 2d induces an e.M.F. Of one volt.

Eddy Currents :

Eddy currents are the currents precipitated in a conductor, while placed in a converting magnetic field. They also are known as Focaults Currents.

Following test provide an explanation for the beginning of eddy currents. Introduce a soft iron middle inner a solenoid and join it to the supply of alternating cutting-edge. Place a metal disk over gentle iron center.

Explanation : When the circuit is switched on the present day starts developing and for this reason magnetic flux connected with disk also increases. Thus disk is transformed to small magnet. If gentle iron’s upper face acquires north polarity. Then metallic disk’s lower surface acquires north polarity and because of repulsive pressure metallic disk located over tender iron center is thrown up into the air.

Application of Eddy Currents :

1. Dead Beat Galvanometers :

The oscillation of a moving coil galvanometer usually take a long time to die out. But by means of winding its coil on a metal frame made from copper or aluminium the galvanometer may be made dead beat. It is due to the fact, because of manufacturing of eddy currents in a metal body. The coil of galvanometer involves relaxation very quickly.

2. Speedometer :

In speedometer, a small magnet is geared to the main shaft of the car. The magnet is established in an aluminium cylinder with the assist of hair springs. Due to rotation of magnet eddy currents are produced which led the drum to oppose the motion of referring to magnet drum experience torque and gets deflected at sure angle.

Three. Electric Brakes :

A metallic drum is coupled to the wheels of educate ; so that after train rotates drum also rotates. In order to prevent the educate magnetic area is carried out to rotating drum. The eddy currents produced oppose the movement of drum. Since drum is attached to wheels of train, it involves halt.


Updated: April 4, 2017 — 9:32 am

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