Electromagnetic Induction

Electromagnetic Induction MDCAT MCQs with answers

79 past paper MCQs from Physics unit 11, Electromagnetic Induction, across 3 topics. They are arranged topic by topic; bigger topics show a sample here and link to their full set and to study notes. Tap “Show answer” for the correct option and a short solution.

Practise as a quiz

Faraday’s Law of Electromagnetic Induction

1.A one metre long copper rod is moved with a speed of $20\ \mathrm{m\,s^{-1}}$ in a magnetic field of strength 0.6 tesla. What is the value of the induced emf? (MDCAT 2022)

  1. 10 V
  2. 12 V
  3. 14 V
  4. 16 V
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Correct answer: (b) 12 V

$\varepsilon=BvL=0.6\times20\times1=12$ V.

2.The unit of $\Delta\Phi/\Delta t$ can be written as: (MDCAT 2022)

  1. $\mathrm{N\,m\,A^{-2}\,s^{-1}}$
  2. $\mathrm{N\,m\,A\,s^{-2}}$
  3. $\mathrm{N\,m\,A^{-1}\,s^{-1}}$
  4. $\mathrm{N\,m\,A^{-2}\,s}$
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Correct answer: (c) $\mathrm{N\,m\,A^{-1}\,s^{-1}}$

The rate of change of flux is an emf, and $1\ \mathrm{V}=1\ \mathrm{J\,C^{-1}}=1\ \mathrm{N\,m\,A^{-1}\,s^{-1}}$.

3.A copper hoop is held in a vertical east-west plane in a uniform magnetic field whose field lines run along the north-south direction. The largest induced emf is produced when the hoop is: (MDCAT 2022)

  1. rotated about a north-south axis
  2. rotated about an east-west axis
  3. moved rapidly, without rotation, towards the east
  4. moved rapidly, without rotation, towards the south
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Correct answer: (b) rotated about an east-west axis

Turning about an east-west axis swings the plane of the hoop through the field and changes the flux fastest; the other motions leave the flux unchanged.

All 37 Faraday’s Law of Electromagnetic Induction MCQs → Faraday’s Law of Electromagnetic Induction notes →

Lenz’s Law

4.The working principle of the magnetic levitation train is: (MDCAT 2022)

  1. Faraday's law
  2. Planck's law
  3. Ohm's law
  4. Lenz's law
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Correct answer: (d) Lenz's law

The induced currents oppose the approaching magnets, and that repulsion is Lenz's law at work.

5.The statement that the induced current will flow in such a direction as to oppose the cause that produces it is: (MDCAT 2024)

  1. Ampere's law
  2. Faraday's law
  3. Lenz's law
  4. Joule's law
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Correct answer: (c) Lenz's law

That is Lenz's law, and it is the conservation of energy applied to induction.

6.A metallic circular ring is suspended by a string in a vertical plane. When a magnet is brought towards the ring, the ring will: (UHS MDCAT 2017)

  1. remain stationary
  2. get displaced away from the magnet
  3. get displaced towards the magnet
  4. nothing can be said
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Correct answer: (b) get displaced away from the magnet

By Lenz law the induced current opposes the approach, so the ring is repelled and swings away.

All 18 Lenz’s Law MCQs → Lenz’s Law notes →

The Transformer

7.In a transformer there is no ______ connection between the two coils, but they are ______ linked. (MDCAT 2022)

  1. magnetic, electrically
  2. electrical, magnetically
  3. magnetic, magnetically
  4. electrical, optically
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Correct answer: (b) electrical, magnetically

The two windings are insulated from each other and the flux in the core is what couples them.

8.In principle, a transformer consists of two coils of copper, electrically insulated from each other, wound on the same: (MDCAT 2023)

  1. iron core
  2. copper core
  3. gold core
  4. steel core
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Correct answer: (a) iron core

A soft iron core carries almost all the flux of the primary through the secondary.

9.In an ideal transformer: (MDCAT 2024)

  1. the power input is equal to the power output
  2. the power input is less than half the power output
  3. the power input is greater than the power output
  4. the power input is more than half the power output
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Correct answer: (a) the power input is equal to the power output

An ideal transformer is lossless, so $V_pI_p=V_sI_s$.

All 24 The Transformer MCQs → The Transformer notes →

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