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

Commutator was invented by:

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

Electromagnetic induction is exactly according to law of:

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

A simple device that prevents the direction of current from changing is called.

• Commutator A
• Rotor B
• Armature C
• Detector 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

DC generator by william Sturgeon in:

• 1894 A
• 1961 B
• 1834 C
• 1961 D

Efficiency of transformer does not affected by

• Input voltage A
• Core of transformer B
• Insulation between sheet C
• Resistance of coils D

The illustration of the phenomenon of mutual induction is in the device of

• Transformer A
• Inductor B
• A.C. Generator C
• Ammeter D

When the back emf in a current is zero, it draws

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

Self inductance of a long solenoid is given by

• 
  A
• 
  B
• 
  C
• None of the 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

The motional emf is give by

• qvB A
• IBL B
• eBL C
• vBL D

• 
  A
• 
  B
• 
  C
• 
  D

Transformer is used to change

• Electric power A
• Magnetic field B
• Alternating voltage C
• Phase of A.C. 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

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

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

The device in the circuit that consume electrical energy are known as.

• Dissipaters A
• Generator B
• Load C
• Motors D