Electromagnetic Induction MCQs for MDCAT Practice

Physics section, Electromagnetic Induction chapter. Sample questions from past PMC papers.

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:
   • A.0.056 V
   • B.0.026 V
   • C.0.045 V
   • D.0.016 V
   Sign up free to see the explanation, distractor analysis, and add this to your spaced repetition deck.
2. Question 2
   In transformer, two coils are ______ linked with each other?
   • A.Electrically
   • B.Magnetically
   • C.Thermally
   • D.Mechanically
   Sign up free to see the explanation, distractor analysis, and add this to your spaced repetition deck.
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:
   • A.1 V
   • B.1.5 V
   • C.0.1 V
   • D.0.15 V
   Sign up free to see the explanation, distractor analysis, and add this to your spaced repetition deck.
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
   • A.Decreases the resistance of the solenoid
   • B.Reduces the effect of eddy current
   • C.Improves the flux linkage between the turns of the coil
   • D.Increases the mutual inductance between the solenoid and the core
   Sign up free to see the explanation, distractor analysis, and add this to your spaced repetition deck.
5. Question 5
   Lenz's law primarily refers to the direction of:
   • A.Voltage
   • B.Induced current
   • C.Power
   • D.Energy
   Sign up free to see the explanation, distractor analysis, and add this to your spaced repetition deck.
6. Question 6
   What is the back emf effect in motors?
   • A.It converts electrical energy into heat energy.
   • B.It reduces the motor's starting torque.
   • C.It increases the motor's speed indefinitely.
   • D.It opposes the applied voltage and limits the armature current.
   Sign up free to see the explanation, distractor analysis, and add this to your spaced repetition deck.
7. Question 7
   If the speed of the moving conductor across the magnetic field decreases, the motional e.m.f
   • A.Decreases
   • B.Increases
   • C.Remains unchanged
   • D.None of these
   Sign up free to see the explanation, distractor analysis, and add this to your spaced repetition deck.
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
   • A.R1/R2
   • B.R2/R1
   • C.R22/R1
   • D.R21/R2
   Sign up free to see the explanation, distractor analysis, and add this to your spaced repetition deck.