Sol. $$ \begin{aligned} & \overrightarrow{\mathrm{E}}=6.6 \hat{\mathrm{j}} \\ & \mathrm{v}=20 \mathrm{MHz} \\ & \overrightarrow{\mathrm{c}}=3 \times 10^8 \hat{\mathrm{i}} \\ & |\overrightarrow{\mathrm{~B}}|=\frac{|\overrightarrow{\mathrm{E}}|}{\mathrm{c}}=2.2 \times 10^{-8} \mathrm{~T} \\ & \overrightarrow{\mathrm{E}} \times \overrightarrow{\mathrm{B}}=\overrightarrow{\mathrm{c}} \\ & \overrightarrow{\mathrm{~B}}=2.2 \times 10^{-8} \hat{\mathrm{k}} \mathrm{~T} \end{aligned} $$