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Free download in PDF Electromagnetic Induction Multiple Choice Questions and Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams like IIT-JEE, AIIMS etc. These short solved questions or quizzes are provided by Gkseries.
(1)
The property of coil by which a counter e.m.f. is induced in it when the current through the coil changes is known as
[A]
self-inductance
[B]
mutual inductance
[C]
series aiding inductance
[D]
capacitance
(2)
The inductance of a coil will increase under all the following conditions except
[A]
when more length for the same number of turns is provided
[B]
when the number of turns of the coil increase
[C]
when more area for each turn is provided
[D]
when permeability of the core increases
Answer: when more length for the same number of turns is provided
(3)
Higher the self-inductance of a coil,
[A]
lesser its weber-turns
[B]
lower the e.m.f. induced
[C]
greater the flux produced by it
[D]
longer the delay in establishing steady current through it
Answer: longer the delay in establishing steady current through it
(4)
Both the number of turns and the core length of an inductive coil are doubled.
Its self-inductance will be
[A]
unaffected
[B]
doubled
[C]
halved
[D]
None of the above
(5)
The direction of induced e.m.f. can be found by
[A]
Laplace’s law
[B]
Lenz’s law
[C]
Fleming’s right hand rule
[D]
All of the above
(6)
The magnitude of the induced e.m.f. in a conductor depends on the
[A]
flux density of the magnetic field
[B]
amount of flux cut
[C]
amount of flux linkages
[D]
rate of change of flux-linkages
Answer: rate of change of flux-linkages
(7)
The law that the induced e.m.f. and current always oppose the cause producing them is due to
[A]
Faraday
[B]
Lenz
[C]
Newton
[D]
None Of The Above
(8)
Which of the following circuit elements will oppose the change in circuit current ?
[A]
Capacitance
[B]
Inductance
[C]
Resistance
[D]
None of these
(9)
For a purely inductive circuit which of the following is true ?
[A]
Apparent power is zero
[B]
Relative power is.zero
[C]
Actual power of the circuit is zero
[D]
None of the Above
Answer: Actual power of the circuit is zero
(10)
The core of a coil has a length of 200 mm. The inductance of coil is 6 mH. If the core length is doubled, all other quantities, remaining the same, the inductance will be
[A]
3 mH
[B]
12 mH
[C]
24mH
[D]
None Of The Above
(11)
Two coils have inductances of 8 mH and 18 mH and a co-efficient of coupling of 0.5. If the two coils are connected in series aiding, the total inductance will be
[A]
32 mH
[B]
38 mH
[C]
40 mH
[D]
None of the Above
(12)
A coil with negligible resistance has 50V across it with 10 mA. The inductive reactance is
[A]
50 ohms
[B]
500 ohms
[C]
5000 ohms
[D]
None of the above
(13)
The co-efficient of coupling between two air core coils depends on
[A]
self-inductance of two coils only
[B]
mutual inductance between two coils only
[C]
mutual inductance and self inductance of two coils
[D]
none of the above
Answer: mutual inductance and self inductance of two coils
(14)
Which of the fpllowing inductor will have the least eddy current losses ?
[A]
Air core
[B]
Laminated iron core
[C]
Iron core
[D]
All of the above
(15)
Which circuit element(s) will oppose the change in circuit current ?
[A]
Resistance only
[B]
Inductance only
[C]
Capacitance only
[D]
None of these
(16)
A coil is wound on iron core which carries current I. The self-induced voltage in the coil is not affected by
[A]
variation in coil current
[B]
variation in voltage to the coil
[C]
change of number of turns of coil
[D]
None of the above
Answer: variation in voltage to the coil
(17)
An E.M.F. can be induced by _________
[A]
Change in the magnetic field only
[B]
Change in the area of cross section only
[C]
Change in angle between magnetic field and area only
[D]
Change in the magnetic field, area or angle between them
Answer: Change in the magnetic field, area or angle between them
(18)
The total number of magnetic field lines passing through an area is termed as?
[A]
Voltage
[B]
EMF
[C]
Magnetic flux
[D]
None of the above
(19)
If a conductor 0.2m long moves with a velocity of 0.3m/s in a magnetic field of 5T, calculate the emf induced if magnetic field, velocity and length of conductor are mutually perpendicular to each other.
[A]
0.3V
[B]
0.03V
[C]
30V
[D]
None of the above
(20)
What does emf stand for?
[A]
Electronic magnetic force
[B]
Electromotive force
[C]
Electromagnetic force
[D]
None Of The Above
Answer: Electromotive force
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