Free Electromagnetic Induction MCQs with Answers
288 Electromagnetic Induction MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Changing magnetic flux induces an emf according to Faraday's law, while Lenz's law gives the direction that opposes the change producing it. Transformers apply induction between coils to step alternating voltage up or down, with turns ratio, current transformation and energy losses determining practical operation.
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Read the Electromagnetic Induction notesFree MDCAT chapter notes with key terms288 questions · page 2 of 15
- A. Doubles
- B. Halves
- C. Remains the same
- D. Becomes four times
Explanation: With the turns ratio fixed, doubling the primary voltage doubles the secondary voltage, and for a given load resistance the secondary…
Correct answer: Doubles- A. Enhance the motion
- B. Try to stop the approach
- C. Become zero
- D. Become alternating
Explanation: By Lenz's law the induced current sets up a field that opposes the change producing it, so the loop is repelled and work must be done to…
Correct answer: Try to stop the approach- A. Battery
- B. Capacitor
- C. Dynamo
- D. Transformer
Explanation: An electric motor and a dynamo are reversible electromagnetic machines: a motor converts electrical energy into mechanical energy, while a…
Correct answer: Dynamo- A. Zero
- B. Maximum
- C. Minimum
- D. Optimum
Explanation: Back emf is produced when the motor rotates and its armature cuts magnetic flux.
Correct answer: Zero- A. zero
- B. 5 H
- C. 5000 H
- D. 5 mH
Explanation: The self-induced emf has magnitude E = L|ΔI/Δt|. Here |ΔI| = |2 A - 3 A| = 1 A and Δt = 1 ms = 0.001 s, so |ΔI/Δt| = 1 A ÷ 0.001 s = 1000…
Correct answer: 5 mH- A. 0.5 mH
- B. 0.5H
- C. 2.0H
- D. 8.0H
Explanation: The self-induced emf satisfies ε = L(di/dt), so L = ε/(di/dt) = 2 V/(4 A s^-1) = 0.5 V s A^-1 = 0.5 H.
Correct answer: 0.5H- A. Each increase
- B. Each decrease
- C. Each remains the same
- D. One increases whereas that in the other decreases
Explanation: As the loops approach, the magnetic flux through each loop increases. By Lenz's law, the induced effect opposes this increase, producing a…
Correct answer: Each decrease- A. Eddy currents
- B. Hysteresis
- C. Resistance in winding
- D. None of these
Explanation: An alternating magnetic flux in the iron core induces circulating currents within the core itself.
Correct answer: Eddy currents- A. 0
- B. 1
- C. 2
- D. 3
Explanation: An Ac generator consists of two poles i.e is the north pole and south pole of a magnet so that we can have a uniform magnetic field.
Correct answer: 2- A. Coiled rings
- B. Split rings
- C. Slip rings
- D. Solenoid rings
Explanation: Alternating Current Generators consist of an Armature Coil. It has slip rings, which maintains contact between the Armature coil and…
Correct answer: Slip rings- A. 2 H
- B. 0.2 H
- C. 0.002 H
- D. 5 H
- E. 6 H
Explanation: To find the self-inductance L of the coil, we use the formula L = V / (ΔI/Δt), where V is the induced emf, ΔI is the change in current…
Correct answer: 0.2 H- A. 1000 m/s
- B. 500 m/s
- C. 100 m/s
- D. 15000 m/s
- E. 250000 m/s
Explanation: The emf induced in a conductor moving with a velocity 'v' perpendicular to a magnetic field 'B' is given by the equation: emf = BvL where…
Correct answer: 1000 m/s- A. Zero
- B. 1
- C. More than 1
- D. Infinite
Explanation: The coupling coefficient (k) is a measure of how efficiently magnetic flux is transferred between two coils.
Correct answer: 1- A. Step up
- B. Step down
- C. Equalize
- D. None of these options is correct
Explanation: The purpose of the transformer is to step down the AC voltage from the mains supply and feed it to the rectifier.
Correct answer: Step down- A. Voltage
- B. Current
- C. Power
- D. Capacitance
Explanation: A transformer changes voltages and current but the power remains constant.
Correct answer: Power- A. Electric induction
- B. Magnetic induction
- C. Electromagnetic induction
- D. Dipole induction
Explanation: Option C is correct since electromagnetic induction is a process in which a conductor is put in a particular position and the magnetic…
Correct answer: Electromagnetic induction- A. Halves
- B. Triples
- C. Doubles
- D. Remains unchanged
Explanation: According to Faraday's Law of Electromagnetic Induction, the induced electromotive force (EMF) in a coil is equal to the rate of change of…
Correct answer: Doubles- A. Self Induction
- B. Mutual Induction
- C. Motional EMF
- D. Electrostatic potential
Explanation: The correct answer is Motional EMF. When a conductor of length L moves across a magnetic field B, a potential difference appears across…
Correct answer: Motional EMF- A. Maximum magnetic flux
- B. Change in magnetic flux
- C. Initial magnetic flux
- D. Rate of change of magnetic flux
Explanation: The induced electromotive force (emf) in a circuit depends upon Rate of change of magnetic flux.According to Faraday's law of…
Correct answer: Rate of change of magnetic flux- A. Motion of loop and magnet
- B. Keeping the magnet stationary and moving the coil
- C. Keeping the coil stationary and moving magnet
- D. All of above
Explanation: In a magnet-coil experiment, the electromagnetic force (emf) can be produced by All of the these.Motion of loop and magnet: When either…
Correct answer: All of above