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Free Faraday's Law MCQs with Answers

48 Faraday's Law MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.

Faraday's law states that an induced electromotive force equals the rate of change of magnetic flux linkage through a circuit. Questions cover changing field, area, angle or motion, the negative sign associated with Lenz's law, and the distinction between induced emf and the current that may flow in a closed circuit.

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48 questions · page 3 of 3

41. In an AC generator the emf will be maximum when factor sinωt is equal to:

  • A. Zero
  • B. 2
  • C. 1
  • D. 1/2

Explanation: B is the correct option. This option is correct. The emf will be maximum when the value of the sine function is at its maximum.

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Correct answer: 1

42. Electric generators and transformers are based on the principles of:

  • A. Coulomb's law
  • B. Faraday's Law
  • C. Ampere's law
  • D. Hook's law

Explanation: Transformers and generators work on the principle of Faraday s Law.

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Correct answer: Faraday's Law

43. When a generator is being driven at 1200rpm, the generated eml is 130 volts. What is the generated emf, if the speed is reduced to 600rpm, while the field flux remains unchanged?

  • A. 65V
  • B. 260V
  • C. 60V
  • D. 10V

Explanation: We know that generated EMF in the DC generator is given by the formula: E = ΦPNZ/60A Where Φ= flux P= No. of poles N= speed Z= No.

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Correct answer: 65V

44. The change of magnetic flux through a circuit will produce:

  • A. Magnetic field
  • B. Electric field
  • C. Induced emf
  • D. Altemating current

Explanation: Protip: Static/ not moving charge: electric field Charge moving with constant velocity: electric and magnetic field

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Correct answer: Magnetic field

45. A wire loop is moved parallel to a uniform magnetic field. The induced emf in the loop will:

  • A. Be maximum
  • B. Be zero
  • C. Depend on the size of the coil
  • D. None of above

Explanation: Since the coil is moving parallel to a uniform magnetic field, the magnetic flux associated with the coil will remain zero during the…

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Correct answer: Be zero

46. The current produced due to induced emf depends upon

  • A. Area of the coil:
  • B. Shape of the coil
  • C. Turns of coil:
  • D. Strength of magnetic field in which coil rotates

Explanation: According to Faraday's law of electromagnetic induction, the magnitude of the induced electromotive force (emf) and hence the current…

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Correct answer: Strength of magnetic field in which coil rotates

47. The time rate of change of magnetic flux has the same dimension as that of:

  • A. Current
  • B. Resistance
  • C. Magnetic induction
  • D. Potential difference

Explanation: The time rate of change of magnetic flux has the same dimensions as potential difference, which is measured in volts (V).

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Correct answer: Potential difference

48. As a loop of wire with a resistance of 10Ω moves in a constant non-uniform magnetic field, it loses kinetic energy at a uniform rate of 4.0 ms/s. The induced current in the loop is:

  • A. 0 mA
  • B. 2 mA
  • C. 2.8 mA
  • D. 20 mA

Explanation: The induced current in the loop is 2.8 mA. The rate of loss of kinetic energy is equal to the power dissipated in the loop, which is given…

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Correct answer: 2.8 mA
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