$\begin{array}{l}
B_{0}=12 \times 10^{-8} \sin \left(1.20 \times 10^{7} z-3.60 \times 10^{15} \mathrm{t}\right) \mathrm{T} \\
\mathrm{B} 0=12 \times 10^{-8} \mathrm{~T} \\
\mathrm{lav}=1.71 \mathrm{~W} / \mathrm{m}^{2}
\end{array}$
$\begin{array}{l}
B_{0}=12 \times 10^{-8} \sin \left(1.20 \times 10^{7} z-3.60 \times 10^{15} \mathrm{t}\right) \mathrm{T} \\
\mathrm{B} 0=12 \times 10^{-8} \mathrm{~T} \\
\mathrm{lav}=1.71 \mathrm{~W} / \mathrm{m}^{2}
\end{array}$