Physics

Physics

Problem

Which of the following relations between the peak electric field E0E_0 and peak magnetic field B0B_0 of an electromagnetic wave in vacuum is correct? a) E0=cB02E_0 = \dfrac{c B_0}{\sqrt{2}} b) E0=2cB0E_0 = 2 c B_0 c) E0=cB0E_0 = c B_0 d) E0=πcB0E_0 = \pi c B_0
Intuitive explanation

An electromagnetic wave is fundamentally a coupled dance between electric and magnetic fields that sustain each other as they propagate. The key insight is that in vacuum, these fields are locked together by the wave equation—they must oscillate in phase and their amplitudes are related through the wave speed. Since both fields carry the same energy density and travel at cc, the ratio E0/B0E_0/B_0 must equal the speed of light itself.

Intuitive explanation

An electromagnetic wave is fundamentally a coupled dance between electric and magnetic fields that sustain each other as they propagate. The key insight is that in vacuum, these fields are locked together by the wave equation—they must oscillate in phase and their amplitudes are related through the wave speed. Since both fields carry the same energy density and travel at cc, the ratio E0/B0E_0/B_0 must equal the speed of light itself.

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