Easy MCQ +4 / -1 PYQ · JEE Mains 2024

A plane electromagnetic wave propagating in $\mathrm{x}$-direction is described by

$$E_y=\left(200 \mathrm{Vm}^{-1}\right) \sin \left[1.5 \times 10^7 t-0.05 x\right] \text {; }$$

The intensity of the wave is :

(Use $\epsilon_0=8.85 \times 10^{-12} \mathrm{C}^2 \mathrm{~N}^{-1} \mathrm{~m}^{-2}$)

  1. A $35.4 \mathrm{~Wm}^{-2}$
  2. B $53.1 \mathrm{~Wm}^{-2}$ Correct answer
  3. C $26.6 \mathrm{~Wm}^{-2}$
  4. D $106.2 \mathrm{~Wm}^{-2}$

Solution

<p>$$\begin{aligned} & \mathrm{I}=\frac{1}{2} \varepsilon_0 \mathrm{E}_0^2 \times \mathrm{c} \\ & \mathrm{I}=\frac{1}{2} \times 8.85 \times 10^{-12} \times 4 \times 10^4 \times 3 \times 10^8 \\ & \mathrm{I}=53.1 \mathrm{~W} / \mathrm{m}^2 \end{aligned}$$</p>

About this question

Subject: Physics · Chapter: Electromagnetic Waves · Topic: Maxwell's Equations

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