An electromagnetic wave is travelling in the +z direction. Which pair of electric and magnetic field orientations is physically possible?
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An electromagnetic wave is travelling in the +z direction. Which pair of electric and magnetic field orientations is physically possible?

G1 Physics · Accepted Answer

Step 1: Direction of energy propagation of EM waves is given by E⃗ × B⃗ (Poynting vector). Step 2: For propagation along +ẑ, electric and magnetic fields must be perpendicular, both transverse to +ẑ. Step 3: E⃗ = E₀î and B⃗ = B₀ĵ satisfy î × ĵ = k̂, so choose D. Final answer: (D) E⃗ = E₀î, B⃗ = B₀ĵ.