The propagation direction of an electromagnetic wave is parallel to which vector product?
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The propagation direction of an electromagnetic wave is parallel to which vector product?

G1 Physics · Accepted Answer

Step 1: The propagation/energy flow of an EM wave is directed along the Poynting vector S⃗ = (1/μ₀)(E⃗ × B⃗). Step 2: Because E⃗ × B⃗ is orthogonal to each, propagation is transverse to both electric and magnetic fields. Step 3: Hence choose B (E⃗ × B⃗). Final answer: (B) E⃗ × B⃗.