In a plane electromagnetic wave, the electric field oscillates sinusoidal at a frequency of $2.0 \times 10^{10}\;Hz$ and amplitude $48 vm^{-1}$. What is the wavelength of the wave ?Show that the total average energy density of magnetic field $( c= 3 \times 10^8 ms^{-1})$

Question

$\begin{array}{1 1} 1.6 \times 10^{-7} T \\ 1.5 \times 10^{-3} T \\ 1.7 \times 10^{-2} m \\ 1.5 \times 10^{-4} m \end{array} $