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

When motor is just started, back emf is almost.

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

B2/2p is the expression of.

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

With the speed of motor, magnitude of back emf

• Remain same A
• Increase B
• Decrease C
• First increases then decreases D

Efficiency of transformer does not affected by

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

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

• Commutator A
• Rotor B
• Armature C
• Detector D

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

Mutual induction has a practical role in the performance of the.

• Radio choke A
• Transformers B
• A.C. Generator C
• D.C. Generator D

The negative sign with induced emf in Faraday's law is in accordance with

• Lenz's law A
• Amperes law B
• Boyle's law C
• Gauss law D

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

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

If magnetic field is doubled then magnetic energy density becomes.

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

A current generator device converts:

• Mechanical energy into chemical energy A
• Chemical energy into electrical energy B
• Mechanical energy into electrical energy C
• Both b and c D

For step down transformer

• Ns>Np A
• Np > Ns B
• Ns = Np C
• Ns > > > Np D

The device in which induced emf is statically induced emf is:

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

Unit of self inductance is

• Weber A
• Tesla B
• Henry C
• Farad D

The induction can be increased by winding the wire around a core made of.

• Copper A
• Silicon B
• Iron C
• Aluminum D

Electric current produces magnetic field, was suggested by.

• Faraday A
• Oersted B
• Henry C
• Lenz D

split rings are used in

• A.C. generator A
• A.C. motor B
• Transformer C
• D.C. motor D