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

A step up transformer is used 120 V line to provide 240 V. If primary coil has 100 turns the number of turns is secondary is.

• 50 A
• 100 B
• 150 C
• 200 D

Eddy current is produced when:

• A metal is light in varying magnetic field A
• A metal is kept in steady magnetic field B
• A circular coil is placed in a steady magnetic field C
• A current is passed through a circualr coil D

When a conductor moves across a magnetic field an emf is set up this emf is called.

• Variable emf A
• Constant emf B
• Back emf C
• Induced emf D

The movement of conductor in magnetic field produces electrical current was discovered in:

• 1931 A
• 1731 B
• 1842 C
• 1831 D

In case of inductor , energy is stored in the

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

In A.C. generator , when plane of coil is perpendicular to magnetic field, then output of generator is.

• NwAB A
• 2pi f B
• Maximum C
• Zero D

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

When the back emf is zero, its draws.

• Zero current A
• Minimum current B
• Maximum current C
• Steady current D

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

The emf induced by the motion of a conductor across a magnetic field is called:

• Motional emf A
• Rotational emf B
• Induced emf C
• All of above 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

The magnitude of motional emf is given by

• 
  A
• 
  B
• 
  C
• 
  D

Commutator was invented by:

• William bills A
• William Gates B
• William tells C
• William Sturgeon D

The current induced can be increased by:

• Using a stronger magnetic field A
• Moving the loop faster B
• Replacing the loop bay coi of many turns C
• All of above D

Step up transfer has a transformation ratio of 3:2. What is the voltage in secondary , If voltage in primary is 30 V?

• 45 V A
• 15 V B
• 90 V C
• 300 V D

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

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