Question:
The electric field of a plane electromagnetic wave propagating along the $x$ direction in vacuum is $\overrightarrow{\mathrm{E}}=\mathrm{E}_{0} \hat{\mathrm{j}} \cos (\omega \mathrm{t}-\mathrm{kx}) .$ The magnetic field $\overrightarrow{\mathrm{B}}$, at the moment $\mathrm{t}=0$ is :
Correct Option: , 3
Solution:
$\Rightarrow \overrightarrow{\mathrm{B}}=\mathrm{B}_{0} \cos (\mathrm{wt}-\mathrm{kx}) \hat{\mathrm{k}}$
Now put $\mathrm{t}=0 .$