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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 $E =6\; Vm^{-1}$ along $y -$ direction. Its corresponding magnetic filed component, $B$ would be
$2 \times {10^{ - 8}}\,T$ along $z -$ direction
$6 \times {10^{ - 8}}\,T$ along $x -$ direction
$6 \times {10^{ - 8}}\,T$ along $z -$ direction
$2 \times {10^{ - 8}}\,T$ along $y -$ direction
Solution
The direction of propagation of an $EM$ wave is direction of $\overrightarrow{\mathrm{E}} \times \overrightarrow{\mathrm{B}}$ $\hat{\mathrm{i}}=\hat{\mathrm{j}} \times \hat{\mathrm{B}}$
$\Rightarrow \hat{\mathrm{B}}=\hat{\mathrm{k}}$
$C=\frac{E}{B} \Rightarrow B=\frac{E}{C}=\frac{6}{3 \times 10^{8}}$
$\mathrm{B}=2 \times 10^{-8}\, \mathrm{T}$ along $\mathrm{z}$ direction.
