JEE MAIN - Physics (2019 - 8th April Morning Slot - No. 9)

A plane electromagnetic wave travels in free space along the x-direction. The electric field component of the wave at a particular point of space and time is E = 6 V m–1 along y-direction. Its corresponding magnetic field component, B would be :
2 × 10–8 T along y-direction
6 × 10–8 T along z-direction
2 × 10–8 T along z-direction
6 × 10–8 T along x-direction

Explanation

The direction of propagation of an EM wave is direction of $$\overrightarrow E \times \overrightarrow B $$

$$\widehat i = \widehat j \times \widehat B$$

$$ \Rightarrow \widehat B = \widehat k$$

$$C = {E \over B} \Rightarrow B = {E \over C} = {6 \over {3 \times {{10}^8}}}$$

B = 2 × 10–8 T along z direction.

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