Verified Solution • 2025–26 Session moderate

QJEEM21Ph25aa: JEE Main 2021 Physics - Class 12 JEEM21Ph25aa Solution: A light beam is described by . An electron is allowed to move…

A light beam is described by E=800sin⁡ω(t−xc)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?

Multiple Choice Options

  • A 1.28 ×\times 10 −- 18 N
  • B 1.28 ×\times 10 −- 21 N
  • C 12.8 ×\times 10 −- 17 N
  • D 12.8 ×\times 10 −- 18 N

Step-by-Step Verified Solution

E0C=B0{{{E_0}} \over C} = {B_0}

Fmax⁡=eB0V{F_{\max }} = e{B_0}V

=1.6×10−19×8003×108×3×107= 1.6 \times {10^{ - 19}} \times {{800} \over {3 \times {{10}^8}}} \times 3 \times {10^7}

=12.8×10−18= 12.8 \times {10^{ - 18}} N

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