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Question 20187
JEE Physics · Medium

Electromagnetic Waves and Wave Optics: Poynting Vector MCQ

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Poynting VectorMediumQuestion 20187

Question

The Poynting vector S = (1/μ₀)(E × B) represents:
  1. A
    Magnetic energy density
  2. B
    Electric energy density
  3. C
    Rate of energy flow per unit area (intensity)
    Correct
  4. D
    Amplitude of the wave

Correct answer

Rate of energy flow per unit area (intensity)

Explanation

The Poynting vector S = (E × B)/μ₀ gives the direction and rate of electromagnetic energy transport per unit area (W/m²). Its time average is the intensity I = c ε₀ E₀²/2.

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