# Electromagnetic Induction MCQ Class 12 Physics

Please refer to Chapter 6 Electromagnetic Induction MCQ Class 12 Physics with answers below. These multiple-choice questions have been prepared based on the latest NCERT book for Class 12 Physics. Students should refer to MCQ Questions for Class 12 Physics with Answers to score more marks in Grade 12 Physics exams. Students should read the chapter Electromagnetic Induction and then attempt the following objective questions.

## MCQ Questions Class 12 Physics Chapter 6 Electromagnetic Induction

The Electromagnetic Induction MCQ Class 12 Physics provided below covers all important topics given in this chapter. These MCQs will help you to properly prepare for exams.

Question. Faraday’s laws are consequence of the conservation of
(a) charge
(b) energy
(c) magnetic field
(d) both (b) and (c)

B

Question. Air-core coils are practically free from
(a) Hysteresis losses
(b) Eddy current losses
(c) Both A and B
(d) None of the above

C

Question. Lenz’s law is a consequence of the law of conservation of
(a) charge
(b) mass
(c) energy
(d) momentum

C

Question. The time required for a current to attain the maximum value in a d.c. circuit containing L and R, depends upon :
(a) R only
(b) L only
(c) L/R
(d) none of these

D

Question. The law that the induced e.m.f. and current always oppose the cause producing them is due to
(b) Lenz
(c) Newton
(d) Coulomb

B

Question. Identify the wrong statement.
(a) Eddy currents are produced in a steady magnetic field.
(b) Eddy currents can be minimized by using laminated core.
(c) Induction furnace uses eddy current to produce heat.
(d) Eddy current can be used to produce braking force in moving trains.

A

Question. Which circuit element(s) will oppose the change in circuit current?
(a) Resistance only
(b) Inductance only
(c) Capacitance only
(d) Inductance and capacitance

B

Question. A conductor carries 125 amperes of current under 60° to a magnetic field of 1.1 tesla. The force on the conductor will be nearly
(a) 50 N
(b) 120 N
(c) 240 N
(d) 480 N

B

Question. Two inductors of inductance .L each are connected in series with opposite? magnetic fluxes. The resultant inductance is
(Ignore mutual inductance)
(a) zero
(b) L
(c) 2L
(d) 3L

C

Question. The self inductance associated with a coil is independent of
(a) current
(b) induced voltage
(c) time
(d) resistance of a coil

D

Question. An open coil has
(a) Zero resistance and inductance
(b) Infinite resistance and zero inductance
(c) Infinite resistance and normal inductance
(d) Zero resistance and high inductance

B

Question. The inductance of a coil is proportional to
(a) The length
(b) The number of turns
(c) The resistance of coil
(d) The square of the number of turns

D

Question. Which of the fpllowing inductor will have the least eddy current losses ?
(a) Air core
(b) Laminated iron core
(c) Iron core
(d) Powdered iron core

A

Question. Whenever the magnetic flux linked with an electric circuit changes, an emf is induced in the circuit. This is called
(a) electromagnetic induction
(b) lenz’s law
(c) hysteresis loss
(d) kirchhoff’s laws

A

Question. According to Faraday’s law of electromagnetic induction
(a) electric field is produced by time varying magnetic flux.
(b) magnetic field is produced by time varying electric flux.
(c) magnetic field is associated with a moving charge.
(d) None of these

A

Question. The self inductance of a coil is a measure of
(a) electrical inertia
(b) electrical friction
(c) induced e.m.f.
(d) induced current

A

Question. Which of the following circuit element stores energy in the electromagnetic field?
(a) Inductance
(b) Condenser
(c) Variable resistor
(d) Resistance

A

Question. In a coil of self-induction 5 H, the rate of change of current is 2 As-1. Then emf induced in the coil is
(a) 10 V
(b) -10 V
(c) 5 V
(d) -5 V

B

Question. Direction of current induced in a wire moving in a magnetic field is found using
(a) Fleming’s left hand rule
(b) Fleming’s right hand rule
(c) Ampere’s rule
(d) Right hand clasp rule

B

Question. 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
(a) 10 V
(b) 15 V
(c) 25 V
(d) 50 V

C

Question. Which of the following does not use the application of eddy current?
(a) Electric power meters
(b) Induction furnace
(c) LED lights
(d) Magnetic brakes in trains

C

Question. If number of turns in primary and secondary coils is increased to two times each, the mutual inductance
(a) becomes 4 times
(b) becomes 2 times
(c) becomes A times
(d) remains unchanged 4

A

Question. An e.m.f is produced in a coil, which is not connected to an external voltage source. This is not due to
(a) the coil being in a time varying magnetic field.
(b) the coil moving in a time varying magnetic field.
(c) the coil moving in a constant magnetic field.
(d) the coil is stationary in external spatially varying magnetic field, which does not change with time.

D

Question. Eddy currents do not cause
(a) damping
(b) heating
(c) sparking
(d) loss of energy

C

Question. The self-inductance L of a solenoid of length l and area of cross-section A, with a fixed number of turns N increases as
(a) l and A increase.
(b) l decreases and A increases.
(c) l increases and A decreases.
(d) both l and A decrease.

B

Question. Mutually inductance between two magnetically coupled coils depends on
(a) Permeability of the core
(b) The number of their turns
(c) Cross-sectional area of their common core
(d) All of the above

D

Question. The mutual inductance M12 of coil 1 with respect to coil
(a) decreases when they are brought nearer.
(b) depends on the current passing through the coils.
(c) increases when one of them is rotated about an axis.
(d) is the same as M21 of coil 2 with respect to coil 1.

D

Question. Two 300 uH coils in series without mutual coupling have a total inductance of
(a) 300 uH
(b) 600 uH
(c) 150 uH
(d) 75 u

B

Question. 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

D

Question. The coefficient of self-inductance of a solenoid is 0.18 mH. If a rod of soft iron of relative permeability 900 is inserted, then the coefficient of self-inductance will become nearly
(a) 5.4 mH
(b) 162 mH
(c) 0.006 mH
(d) 0.0002 mH

B

Question. 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

C

Question. Lenz’s law is in accordance with law of conservation of
(a) Charge
(b) Momentum
(c) Energy
(d) Current

C

Question. In case all the flux from the current in coil 1 links with coil 2, the co-efficient of coupling will be
(a) 2.0
(b) 1.0
(c) 0.5
(d) zero

B

Question. Which one of the following is a correct statement?
(a) Electric field is always conservative
(b) Electric field due to a varying magnetic field is conservative
(c) Electric field is conservative due to electrostatic charges while non-conservative due to a time varying magnetic field
(d) Electric field lines are always closed loops

C

Question. Induction furnace is based on the principle of
(a) Self induction
(b) Mutual induction
(c) Eddy current
(d) None of these

C

Question. The frequency of an ac generator is altered with change in
(a) Speed or rotation of coil
(b) Amplitude of a.c.
(c) Size of coil
(d) All of the above

A

Question. The working of generator is based upon
(a) Magnetic effect of current
(b) Heating effect of current
(c) Chemical effect of current
(d) Electromagnetic induction

D

Question. The law that the induced e.m.f. and current always oppose the cause producing them is due to
(b) Lenz
(c) Newton
(d) Coulomb

B

Question. The law that the induced e.m.f. and current always oppose the cause producing them is due to
(b) Lenz
(c) Newton
(d) Coulomb

B

Question. Which of the following circuit element stores energy in the electromagnetic field ?
(a) Inductance
(b) Condenser
(c) Variable resistor
(d) Resistance

A

Question. An open coil has
(a) zero resistance and inductance
(b) infinite resistance and zero inductance
(c) infinite resistance and normal inductance
(d) zero resistance and high inductance

B

Question. The magnetic field is parallel to a surface, then the magnetic flux through the surface is :
(a) zero
(b) small but not zero
(c) infinite
(d) large but not infinite

B

Question. According to Faraday’s law of electromagnetic induction
(a) electric field is produced by time varying magnetic flux.
(b) magnetic field is produced by time varying electric flux.
(c) magnetic field is associated with a moving charge.
(d) None of these

A

Question. A coil with negligible resistance has 50V across it with 10 mA. The inductive reactance is
(a) 50 ohms
(b) 500 ohms
(c) 1000 ohms
(d) 5000 ohms

D

Question. Air-core coils are practically free from
(a) hysteresis losses
(b) eddy current losses
(c) both (a) and (b)
(d) none of the above

C

Question. Which of the following is unit of inductance ?
(a) Ohm
(b) Henry
(c) Ampere turns
(d) Webers/metre

B

Question. If current in a conductor increases then according to Lenz’s law self-induced voltage will
(a) Aid the increasing current
(b) Tend to decrease the amount of current
(c) Produce current opposite to the increasing current
(d) Aid the applied voltage

C

Question. Lenz’s law of electromagnetic induction is as per law of conservation of
(a) energy.
(b) momentum angular.
(c) charge.
(d) electromotive force.

A

Question. Pick out the SI unit of magnetic flux.
(a) Ampere
(b) Tesla meter
(c) Weber
(d) Maxwell

C

Question. A choke is used as a resistance in :
(a) dc circuits
(b) ac circuits
(c) both ac and dc circuits
(d) neither (i) nor (ii)