Question
Electric field in a plane electromagnetic wave is given by ${E}=50 \sin \left(500 {x}-10 \times 10^{10} {t}\right) \,{V} / {m}$ The velocity of electromagnetic wave in this medium is :
(Given ${C}=$ speed of light in vacuum)
✓
Answer
${V}=\frac{\omega}{{K}}=\frac{10 \times 10^{10}}{500}=2 \times 10^{8}$
$V=\frac{2 {C}}{3}$
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