2nd Year Physics Chapter 15 Online MCQ Test for 12th Class Physics Chapter 15 (Electromagnetic Induction)

The winding of the electromagnet in motor are usually called.

• Magnetic coils A
• Field coils B
• Electric coils C
• electric o electric coils D

• Lenz's law A
• Faraday's law B
• Ampere's law C
• None of these D

The motional emf depends upon the

• Length of conductor A
• Speed of conductor B
• Strength of magnet C
• All of these D

When motor is just started, back emf is almost.

• Maximum A
• Zero B
• Minimum C
• Infinite D

If force in the direction of velocity of conductor,  then induced current is directed,

• Anti clockwise A
• Clock wise B
• At equilibrium C
• None of above D

Self inductance of a long solenoid is given by

• 
  A
• 
  B
• 
  C
• None of the above D

The rod of unit length is moving at 30 o through a magnetic field of 1 T. If the velocity of rod is 1 m/s, then induced emf in the rod will be given by

• I V A
• 0.25 V B
• 0.5 V C
• 0.6 V D

A real transformer does not change.

• Voltage level A
• Current level B
• Power level C
• Frequency D

In case of inductor , energy is stored in the

• Electric field A
• Magnetic field B
• Potential field C
• Gravitational field D

What is the co-efficient of mutual inductance, when the magnetic flux changes by 2 x 10^-2 Wb, and change in current is 0.01 A?

• 2 H A
• 3 H B
• 1/2 H C
• Zero D

For inducing emf in a coil the basic requirement is that:

• Flux should link the coil A
• Change in flux should link the coil B
• Coil should form a closed loop C
• Both (b) and (c) are true D

Induced emf in A.C. generator can be increased by

• Decreasing area of coil A
• Decreasing magnetic field B
• Increasing area of coil C
• Slowing down speed of coil D

A 50 mH coil carries a current of 2.0 a , then energy stored in tis magnetic field is.

• 0.1 J A
• 10 J B
• 100 J C
• 1000 J D

For step down transformer

• Ns>Np A
• Np > Ns B
• Ns = Np C
• Ns > > > Np D

Energy stored in inductor is.

• 1/2 L I² A
• 1/2 LI B
• 1/2 L2I C
• 1/2 L2I2 D

If D.C. input for step up transformer, the output is

• Zero A
• High B
• Low C
• May be high or low D

Electromagnetic induction obeys law of conservation

• Charge A
• Energy B
• Momentum C
• Mass D