Second Year Physics Chapter 15 Online MCQ Test for 2nd Year Physics Chapter 15 Electromagnetic Induction Preparation

When the back emf is zero, its draws.

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

When a motor is over loaded then the magnitude of back emf.

• Increases A
• Decreases B
• Remain constant C
• Zero 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 motional emf depends upon the

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

• 
  A
• 
  B
• 
  C
• 
  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 device in which induced emf is statically induced emf is:

• Transforms A
• AC generator B
• Alevator C
• Dynamo D

The direction of induced current is always so as to oppose the change which causes the current is:

• Faraday's law A
• Lenz's  law B
• Ohm's law C
• Kirchhoff's 1st rule D

The winding of the electromagnet in motor are usually called.

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

Which of the following quantities remain constant in step up transformer?

• Current A
• Voltage B
• Power C
• Heat D

A.C is converted into D.C by

• Dynamo A
• Rectifier B
• Motor C
• Transformer D

The magnitude of motional emf is given by

• 
  A
• 
  B
• 
  C
• 
  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

The magnitude of back emf:

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

Lenz's law was given by Heinrich lenz in:

• 1894 A
• 1904 B
• 1854 C
• 1834 D

If magnetic field is doubled then magnetic energy density becomes.

• Four times A
• Two times B
• Three times C
• Six times D