Physics

Problem

A plane electromagnetic wave has frequency of

2.0 \times 10^{10}\text{ Hz}

and its energy density is

1.02 \times 10^{-8}\text{ J/m}^3

in vacuum. The amplitude of the magnetic field of the wave is close to (

\frac{1}{4\pi\epsilon_0} = 9 \times 10^9 \frac{\text{Nm}^2}{\text{C}^2}

and speed of light =

3 \times 10^8 \text{ ms}^{-1}

): a. 150 nT b. 160 nT c. 180 nT d. 190 nT