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

The north pole of a magnet is brought near a metallic ring. The direction of induced current in the ring will be:

• Antoclockwise A
• Clockwise B
• First Clockwise and then Antoclockwise C
• First anticlockwise and then Clockwise 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

Step up transformer is used.

• Step up D.C. voltage A
• Step up A.C. voltage B
• Step up both A.C and D.C. C
• Step up A.C. current D

The mutual inductance between two coils depends upon their

• Size A
• Core material B
• Size, core material and separation C
• Separation D

Energy density of an inductor is:

• UM=1/2μ_∘/B² A
• Um = 2μ_∘/B B
• UM = 1/2B²/μ_∘ C
• Um = 2B²/μ_∘ D

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

In D.C. generator, split rings act as.

• Capacitor A
• Commutator B
• Resistor C
• Inductor D

The application of mutual induction is a.

• D.C. motor A
• Radio B
• Television C
• Transformer D

The magnitude of motional emf is given by

• 
  A
• 
  B
• 
  C
• 
  D

In case of inductor , energy is stored in the

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

The unit of induced emf is

• Ampere A
• Volt B
• Joule/coulomb C
• Both (b) and (c) D

If 10 A current passes through 100 mH inductor, then energy stored is.

• 100 J A
• 5 J B
• 20 J C
• Zero D

Commutator was invented in

• 1834 A
• 1820 B
• 1840 C
• 1835 D

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

When motor is just started, back emf is almost.

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

Lenz's law deals with

• Magnitude of emf A
• Direction emf B
• Direction of induced current C
• Resistance D

The magnitude of back emf:

• Increases with sped of motor A
• Decreases with speed of motor B
• Remains same  C
• None of above D