Medium MCQ +4 / -1 PYQ · JEE Mains 2021

A light beam is described by $E = 800\sin \omega \left( {t - {x \over c}} \right)$. An electron is allowed to move normal to the propagation of light beam with a speed of 3 $\times$ 107 ms$-$1. What is the maximum magnetic force exerted on the electron?

  1. A 1.28 $\times$ 10<sup>$-$18</sup> N
  2. B 1.28 $\times$ 10<sup>$-$21</sup> N
  3. C 12.8 $\times$ 10<sup>$-$17</sup> N
  4. D 12.8 $\times$ 10<sup>$-$18</sup> N Correct answer

Solution

${{{E_0}} \over C} = {B_0}$<br><br>${F_{\max }} = e{B_0}V$<br><br>$$ = 1.6 \times {10^{ - 19}} \times {{800} \over {3 \times {{10}^8}}} \times 3 \times {10^7}$$<br><br>$= 12.8 \times {10^{ - 18}}$ N

About this question

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

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