A plane electromagnetic wave E⃗=Eₘ ĵ cos(ωt-kx) propagates in vacuum along +x. Which pair correctly gives H⃗ at position x for (a) t=0 and (b) t=t₀?
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Question

A plane electromagnetic wave E⃗=Eₘ ĵ cos(ωt−kx) propagates in vacuum along +x. Which pair correctly gives H⃗ at position x for (a) t=0 and (b) t=t₀?

G1 Physics · Accepted Answer

For propagation along +x with E⃗ along +y, H⃗ must be along +z. Also H=E/Z₀=√(ε₀/μ₀)E. Substituting t=0 and t=t₀ gives the pair in option A.