Q.1
The direction of induced e.m.f. can be found by
  • Laplace's law
  • Lenz's law
  • Fleming's right hand rule
  • Kirchhoff s voltage law
Q.2
A coil inducesmV when the current changes at the rate of 1 A/s. The value of inductance is
  • 3500 mH
  • 350 mH
  • 250 mH
  • 150 mH
Q.3
Current changing from 8 A toA in one second inducedvolts in a coil. The value of inductance is
  • 5 mH
  • 10 mH
  • 5 H
  • 10 H
Q.4
A coil is wound on iron core which carries current I. The self-induced voltage in the coil is not affected by
  • Variation in coil current
  • Variation in voltage to the coil
  • Change of number of turns of coil
  • The resistance of magnetic path
Q.5
Two coils have self-inductances ofH and 2 H, the mutual inductance being zero. If the two coils are connected in series, the total inductance will be
  • 6 H
  • 8 H
  • 12 H
  • 24 H
Q.6
Two coils have inductances of 8 mH andmH and a coefficient of coupling of 0.If the two coils are connected in series aiding, the total inductance will be
  • 32 mH
  • 38 mH
  • 40 mH
  • 48 mH
Q.7
If current in a conductor increases then according to Lenz's law self-induced voltage will
  • Aid the increasing current
  • Tend to decrease the amount of current
  • Produce current opposite to the increasing current
  • Aid the applied voltage
Q.8
A conductor 2 meters long moves at right angles to a magnetic field of flux density 1 tesla with a velocity of 12.5 m/s. The induced e.m.f. in the conductor will be
  • 10 V
  • 15 V
  • 25 V
  • 50 V
Q.9
The polarity of the induced voltage can be determined by using the left-hand generator rule.
  • Yes
  • No
Q.10
Both the number of turns and the core length of an inductive coil are doubled. Its self-inductance will be
  • Unaffected
  • Doubled
  • Halved
  • Quadrupled
Q.11
Find the force acting on a conductorlong carrying a current ofamperes at right angles to a magnetic field having a flux density of 0.tesla
  • 100 N
  • 400 N
  • 600 N
  • 1000 N
Q.12
Which of the following inductor will have the least eddy current losses?
  • Air core
  • Laminated iron core
  • Iron core
  • Powdered iron core
Q.13
Which of the following circuit element stores energy in the electromagnetic field?
  • Inductance
  • Condenser
  • Variable resistor
  • Resistance
Q.14
An e.m.f. ofvolts is induced in a coil of inductance 4H. The rate of change of current must be
  • 64 A/s
  • 32 A/s
  • 16 A/s
  • 4 A/s
Q.15
Aturn coil has an inductance ofmH. If the number of turns is increased toturns, all other quantities (area, length etc.) remaining the same, the inductance will be
  • 6 mH
  • 146 mH
  • 24 mH
  • 48 mH
Q.16
For a purely inductive circuit which of the following is true?
  • Apparent power is zero
  • Relative power is zero
  • Actual power of the circuit is zero
  • Any capacitance even if present in the circuit will not be charged
Q.17
Which of the fpllowing inductor will have the least eddy current losses ?
  • Air core
  • Laminated iron core
  • Iron core
  • Powdered iron core
Q.18
Increasing the field or increasing the current will decrease the force on the conductor.
  • Yes
  • No
Q.19
A moving magnetic field will produce the same effect as a conductor that is moving.
  • True
  • False
Q.20
Aturns solenoid develops an average induced voltage ofV. Over what time interval must a flux change of 0.Wb occur to produce such a voltage?
  • 0.01 s
  • 0.1 s
  • 0.5 s
  • All of above
0 h : 0 m : 1 s