Question:
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 $\mathrm{E}=6 \mathrm{Vm}^{-1}$ along $y$-direction. Its corresponding magnetic field component, B would be:
Correct Option: 1
Solution:
(1) The relation between amplitudes of electric and magnetic field in free space is given by
$B_{0}=\frac{E_{0}}{c}=\frac{6}{3 \times 10^{8}}=2 \times 10^{-8} T$
Propagation direction $=\hat{E} \times \hat{B}$
$\hat{i}=\hat{j} \times \hat{B}$
$\Rightarrow \hat{B}=\hat{k}$
$\therefore$ The magnetic field component will be along $z$ direction.