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Electromagnetic Induction MCQs for MDCAT Practice

Physics section, Electromagnetic Induction chapter. Up to eight free sample questions, each with the correct answer and a worked explanation. The full chapter opens in the app.

The bank has 1,011 active questions on this chapter. Your first 500 practice attempts are free, and every attempt includes a worked explanation.

  1. Question 1
    A coil has an area of 0.05 m and it has 800 turns. It is placed perpendicularly in a magnetic field of strength 4x10^(-5)Wb/m^(2), it is rotated through 90° in 0.1 s. The average induced emf in the coil is:
    • 0.056 V
    • 0.026 V
    • 0.045 V
    • 0.016 V (correct answer)
    Correct answer: D
    This question tests Faraday's Law of Induction by calculating the average induced EMF in a coil rotating in a magnetic field.
  2. Question 2
    In transformer, two coils are ______ linked with each other?
    • Electrically
    • Magnetically (correct answer)
    • Thermally
    • Mechanically
    Correct answer: B
    Transformers operate via magnetic flux linkage between coils, not electrical, thermal, or mechanical connections.
  3. Question 3
    A coil of 150 loops is pulled in 0.06s from poles of the magnet, which decreases the magnetic flux linked with the coil from 6×10-4 Wb to 2×10-4 Wb. The average emf induced in the coil is:
    • 1 V (correct answer)
    • 1.5 V
    • 0.1 V
    • 0.15 V
    Correct answer: A
    Calculate induced EMF using Faraday's Law when magnetic flux changes over time in a coil.
  4. Question 4
    The self-inductance of a solenoid is increased when a soft iron core is inserted into it. This is because of the soft iron core
    • Decreases the resistance of the solenoid
    • Reduces the effect of eddy current
    • Improves the flux linkage between the turns of the coil (correct answer)
    • Increases the mutual inductance between the solenoid and the core
    Correct answer: C
    Inserting a soft iron core into a solenoid boosts self-inductance by enhancing magnetic flux linkage, a key principle in electromagnetic induction.
  5. Question 5
    Lenz's law primarily refers to the direction of:
    • Voltage
    • Induced current (correct answer)
    • Power
    • Energy
    Correct answer: B
    Lenz's law determines the direction of induced current, not voltage or power—it follows energy conservation by opposing the change in magnetic flux.
  6. Question 6
    What is the back emf effect in motors?
    • It converts electrical energy into heat energy. (correct answer)
    • It reduces the motor's starting torque.
    • It increases the motor's speed indefinitely.
    • It opposes the applied voltage and limits the armature current.
    Correct answer: A
    Back emf in motors opposes the applied voltage, arising from the motor's coil rotating in a magnetic field and inducing a voltage.
  7. Question 7
    If the speed of the moving conductor across the magnetic field decreases, the motional e.m.f
    • Decreases (correct answer)
    • Increases
    • Remains unchanged
    • None of these
    Correct answer: A
    Motional EMF is directly proportional to the velocity of a conductor moving through a magnetic field. Decreasing speed reduces the induced EMF.
  8. Question 8
    Consider two, single turn, co-planar, concentric coils of radii R1 and R2 with R1 >> R2. The mutual inductance between the two coils is proportional to
    • R1/R2
    • R2/R1
    • R22/R1 (correct answer)
    • R21/R2
    Correct answer: C
    Mutual inductance between concentric coils depends on the square of the smaller radius and inversely on the larger radius, reflecting flux linkage efficiency.

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