electromagnetic induction

Phenomenon of generation of induced electromotive force and induced current a conductor as a result of the variation of the magnetic flux lines that intercepted by the conductor .

• electromotive forces

• electromagnetic waves

• electromagnetic induction

• electromagnetic pollution

Faraday’s laws

• 𝐞𝐦𝐟 = − 𝐍 ∆𝜱𝒎 ∆ t

• 𝐞𝐦𝐟 = − 𝐍 ∆𝜱𝒎 / ∆ t

• 𝐞𝐦𝐟 = − 𝐍 ∆𝜱𝒎 + ∆ t

• 𝐞𝐦𝐟 = − 𝐍 ∆𝜱𝒎 - ∆ t

Which of the following figures shows the methods of obtaining induce electric current ?

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A coil of 2 turns is placed in a magnetic field which changes from 4 Wb/m2 to 8 Wb/m 2  in 2 seconds. Find the induced e.m.f. in the coil

• -4 V

• -5 V

• -6 V

•  -7 V

A square loop is placed in a uniform magnetic field perpendicular to the plane of the loop as shown. The loop is 0.50 meter2 on a side and the magnetic field 

B has a strength of 2 T. If the loop is rotated through an angle of 90° in 0.1 second what would be the average induced emf in the loop?

• 0.025 V

• 0.4 V

• 5 V

• 10 V

The induced emf generated in a coil on plunging a magnet into or withdrawing it out the coil differ according to the difference in ....

• (the intensity of electric current - the length of the wire - the number of the lines of flux).

• (magnet strength - the velocity with which the magnet moves - the number of turns

  of the coil)

• (cross-sectional area - mass per unit length of the coil - the type of the material of the wire).

• (flux density - time - electric current intensity).

The pointer of a galvanometer needle whose terminals are connected to a solenoid coil

will be deflected if one withdraws the magnet quickly from the coil because..........

• the number of the coil turns is very large.

• the coil intercepts the lines of the magnetic flux.

• the number of turns of the coil is suitable.

• the number of turns of the coil is small.

Which of the following represents faraday's law

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Doubling the diameter of a loop of wire produces , what will happen for emf , assuming all other factors are constant

• emf will increase to double

• emf will decrease to half

• emf will increase to four time

• emf will decrease to quarter

The measuring unit of emf

• V

• A

• m

• T