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⚛️ Physics  ·  Electromagnetic Waves  ·  NEET & JEE

The average intensity of an electromagnetic wave in vacuum in terms of the peak electric field E₀ is:

Answer: (1/2)cε₀E₀².

  • A (1/2)cε₀E₀²
  • B cε₀E₀²
  • C (1/2)ε₀E₀²
  • D cE₀²

Correct answer: A. (1/2)cε₀E₀²

Explanation: Average intensity I = (1/2)cε₀E₀².

Electromagnetic Wave: E ⊥ B ⊥ Direction of TravelpropagationE (electric field, vertical plane)B (magnetic field, horizontal plane, perpendicular to E)

In an electromagnetic wave, the oscillating electric field (E) and magnetic field (B) are perpendicular to each other and to the direction the wave travels - a purely transverse wave that needs no medium, unlike sound.

Concept context

Maxwell's equations, EM spectrum, properties, and applications of each band.

Read the full Electromagnetic Waves notes →