JEE Main · 2019 · 11 Jan 2019 · Shift 2 · EM Waves

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A 27 mW laser beam has a cross-sectional area of . The magnitude of the maximum electric field in this electromagnetic wave is given by:
[Given permittivity of space units, speed of light ]
  1. (A)
  2. (B)
  3. (C)
  4. (D)✓ Correct

Answer: (D)

Solution

The intensity of the beam is its power over its area, W/m. For an electromagnetic wave , so . This gives , so V/m, that is about kV/m.

JEE Main · 2019 · 11 Jan 2019 · Shift 2 · Single correct option

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