Electromagnetic Theory

JKPSC Assistant Professor (Physics) · Physics · 67 practice questions with answers and explanations: 10 Easy, 57 Medium, 0 Hard.

Sample questions

Sample Easy question 1

The speed of electromagnetic waves in vacuum is:

  1. 3 × 10¹⁰ m/s
  2. 3 × 10⁶ m/s
  3. 3 × 10⁸ m/s
  4. 3 × 10⁵ m/s
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Answer: C. c = 1/√(μ₀ε₀).

Sample Easy question 2

Maxwell's addition to Ampère's law is the:

  1. Magnetisation current
  2. Induced charge
  3. Eddy current
  4. Displacement current
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Answer: D. ∇×B = μ₀J + μ₀ε₀ ∂E/∂t.

Sample Easy question 3

The Lorentz force on a charge q moving with velocity v in fields E and B is:

  1. qE × B
  2. q(E − v × B)
  3. qvB
  4. q(E + v × B)
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Answer: D. The magnetic part does no work.

Sample Medium question 4

Maxwell's equations are invariant under:

  1. Lorentz transformations
  2. Galilean transformations
  3. Rotation only
  4. Translation only
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Answer: A. This led to special relativity.

Sample Medium question 5

The power radiated by an accelerated charge is given by the:

  1. Biot–Savart law
  2. Ohm's law
  3. Faraday's law
  4. Larmor formula
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Answer: D. P = q²a²/6πε₀c³.

Sample Medium question 6

The radiation from an oscillating electric dipole has an intensity varying as:

  1. cos²θ
  2. Constant
  3. 1/sin θ
  4. sin²θ
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Answer: D. It is zero along the dipole axis.

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