Easy MCQ +4 / -1 PYQ · JEE Mains 2022

The electric field in an electromagnetic wave is given by E = 56.5 sin $\omega$(t $-$ x/c) NC$-$1. Find the intensity of the wave if it is propagating along x-axis in the free space.

(Given : $\varepsilon$0 = 8.85 $\times$ 10$-$12C2N$-$1m$-$2)

  1. A 5.65 Wm<sup>$-$2</sup>
  2. B 4.24 Wm<sup>$-$2</sup> Correct answer
  3. C 1.9 $\times$ 10<sup>$-$7</sup> Wm<sup>$-$2</sup>
  4. D 56.5 Wm<sup>$-$2</sup>

Solution

<p>$I = {1 \over 2}{\varepsilon _0}E_0^2c$</p> <p>$= {1 \over 2} 8.5 \times {10^{ - 12}} \times {(56.5)^2} \times 3 \times {10^8}$</p> <p>$= 4.24$ W/m<sup>2</sup></p>

About this question

Subject: Physics · Chapter: Electromagnetic Waves · Topic: Properties of EM Waves

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