A plane electromagnetic wave of frequency 500 MHz travels in vacuum along +y. At a particular point, B⃗=8.0×10⁻⁸ k̂ T. Find E⃗ at that point. Take c=3×10⁸ m s⁻¹.
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Question

A plane electromagnetic wave of frequency 500 MHz travels in vacuum along +y. At a particular point, B⃗=8.0×10⁻⁸ k̂ T. Find E⃗ at that point. Take c=3×10⁸ m s⁻¹.

G1 Physics · Accepted Answer

For propagation along +y with B⃗=8×10⁻⁸k̂ T, E⃗×B⃗ must be +ĵ. Thus E⃗ is −î and |E|=cB=(3×10⁸)(8×10⁻⁸)=24 V/m. Hence E⃗=−24î V/m, option A.