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⚛️ Physics  ·  Electromagnetic Waves  ·  NEET & JEE

The speed of electromagnetic waves in vacuum is:

Answer: 3 × 10⁸ m/s (same for all EM waves).

  • A 3 × 10⁸ m/s (same for all EM waves)
  • B 3 × 10⁸ m/s mainly for light in most cases
  • C Depends on the frequency under typical conditions
  • D Depends on the wavelength according to standard textbooks

Correct answer: A. 3 × 10⁸ m/s (same for all EM waves)

Explanation: All electromagnetic waves travel at c = 3 × 10⁸ m/s in vacuum, regardless of their frequency or wavelength. This is a fundamental constant of nature.

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 →