Electromagnetic Waves and Wave Optics: Speed of EM Waves MCQ

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Speed of EM WavesEasyQuestion 20182

Question

Speed of electromagnetic waves in vacuum is:

A
3×10⁸ m/s for all frequencies
Correct
B
Depends on wavelength
C
Depends on amplitude
D
Only valid for visible light

Correct answer

3×10⁸ m/s for all frequencies

Explanation

c = 1/√(μ₀ε₀) ≈ 3×10⁸ m/s for all EM waves (radio, microwave, infrared, visible, UV, X-ray, gamma) in vacuum. Frequency and wavelength vary; c = fλ remains constant.

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