JEE Mains · Physics · STD 12 - 8. Electromagnetic waves
A plane electromagnetic wave propagating in \(\mathrm{x}\)-direction is described by \(\mathrm{E}_{\mathrm{y}}=\left(200\ \mathrm{Vm}^{-1}\right) \sin \left[1.5 \times 10^7 \mathrm{t}-0.05\ \mathrm{x}\right] \text {; }\) The intensity of the wave is :(Use \(\epsilon_0=8.85 \times 10^{-12} \mathrm{C}^2 \mathrm{~N}^{-1} \mathrm{~m}^{-2}\) )
- A \(35.4 \ \mathrm{Wm}^{-2}\)
- B \(53.1 \ \mathrm{Wm}^{-2}\)
- C \(26.6 \ \mathrm{Wm}^{-2}\)
- D \(106.2 \ \mathrm{Wm}^{-2}\)
Answer & Solution
Correct Answer
(B) \(53.1 \ \mathrm{Wm}^{-2}\)
Step-by-step Solution
Detailed explanation
\( \mathrm{I}=\frac{1}{2} \varepsilon_0 \mathrm{E}_0^2 \times \mathrm{c} \) \( \mathrm{I}=\frac{1}{2} \times 8.85 \times 10^{-12} \times 4 \times 10^4 \times 3 \times 10^8 \) \( \mathrm{I}=53.1 \mathrm{~W} / \mathrm{m}^2\)
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