Conceptual Questions | Chapter 14 | Electromagnetic Induction l 12 Class Physics Federal Board

Each of the following questions is followed by four answers. Select the correct answer in each case.
For inducing e.m.f. in a coil the basic requirement is that
A. Flux should link the coil B. Change in flux should link the coil
C. Coil should form a closed loop D. Both B and C are true
When a single turn coil rotates in a uniform magnetic field, at uniform speed the induced e.m.f. will be
A. Alternating B. Steady C. Pulsating D. Zero
Principle of dynamically induced e.m.f. is used in a
A. Choke B. Transformer C. Generator D. Thermo-couple
In Fleming’s left-hand rule thumb always represents direction of
A. Current flow B. Induced e.m.f. C. Magnetic field D. Mechanical force
The field at any point on the axis of a current carrying coil will be
A. Perpendicular to the axis B. Parallel to the axis
C. At the angle of 45 with the axis D. Zero
When a coil rotated in magnetic field the induced current in it
A. Continuously changes B. Remains same
C. Becomes zero D. becomes maximum
In A.C generator increasing the number of turns in the coil
A. decreases the electromotive force (e.m.f.) B. electromotive force (e.m.f.) remains same
C. increases the electromotive force (e.m.f.) D. electromotive force (e.m.f.) becomes zero
The device in which induced e.m.f. is statically induced e.m.f. is
A. transformer B. AC generator C. alternator D. dynamo
What is the coefficient of mutual inductance, when the magnetic flux changes by 2×〖10〗^(-2) Wb and change in current is 0.01A?
A. 2H B. 3H C. 1/2H D. zero
The induced e.m.f. in a coil is proportional to
A. magnetic flux through the coil B. rate of change of magnetic flux through the coil
C. area of the coil D. product of magnetic flux and area of the coil
In a coil current change from 2 to 4A in 0.05s. If the average induced e.m.f. is 8v then coefficient of self-inductance is
A. 0.2H B. 0.1H C. 0.8H D. 0.04H
Which of the following quantities remain constant in step up transformer?
A. current B. voltage C. power D. heat
Step-up transformer has a transformation ratio of 3:2. What is the voltage in secondary, if voltage in primary is 30V?
A. 45V B. 15V C. 90V D. 300V
Eddy current is produced when
A. a metal is kept in varying magnetic field B. a metal is kept in steady magnetic field
C. circular coil is placed in a steady magnetic field D. current is passed through a circular coil.