JEE MAIN - Physics (2021 - 26th August Evening Shift - No. 6)

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?
1.28 $$\times$$ 10$$-$$18 N
1.28 $$\times$$ 10$$-$$21 N
12.8 $$\times$$ 10$$-$$17 N
12.8 $$\times$$ 10$$-$$18 N

Explanation

$${{{E_0}} \over C} = {B_0}$$

$${F_{\max }} = e{B_0}V$$

$$ = 1.6 \times {10^{ - 19}} \times {{800} \over {3 \times {{10}^8}}} \times 3 \times {10^7}$$

$$ = 12.8 \times {10^{ - 18}}$$ N

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