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

In a coil current change from 2 to 4 A in .05 s . If the average induced emf is 8 V then coefficient of self-inductance is:

• 0.2 henry A
• 0.1 henry B
• 0.8 henry C
• 0.04 henry D

Energy density in an inductor is.

• Directly proportional to magnetic field A
• Directly proportional to square of magnetic field B
• Inversely proportional to magnetic field C
• Inversely proportional to square of magnetic field 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

B2/2p is the expression of.

• Lenz's law A
• Magnetic energy B
• Magnetic energy density C
• Back emf D

the core of transformer is laminated so reduce.

• Magnetic loss A
• Hysteresis loss B
• Eddy current loss C
• Electric loss D

Which one is not present in A.C. generator.

• Armature A
• Magnet B
• Slip rings C
• Commutator 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

The mutual inductance of the coils depends upon.

• Stiffness of the coils A
• Density of coils B
• Material of coils C
• Geometry of the coils D

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

Self induction does not depend on

• Number of turns of the coil A
• Area of cross section of the core B
• Nature of material of the core C
• Current through inductor D

The jerks in D.C. motor are created by the use of.

• Armature A
• Commutators B
• Split rings C
• Source of emf 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

Commentator was invented by

• Henry A
• Ousted B
• Maxwell C
• William sturgeon D

Lenz's law presented in

• 1834 A
• 1934 B
• 1826 C
• 1836 D

If speed of rotation of a generator is doubled the output voltage will be.

• Remain same A
• Double B
• Four time C
• One half 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

Commutator was invented in

• 1834 A
• 1820 B
• 1840 C
• 1835 D