All Problems Electromagnetic Waves. Radiation
Problem 4.197
A plane harmonic electromagnetic wave with plane polarization propagates in vacuum. The electric component of the wave has a strength amplitude \(E_{m}=50 \mathrm{mV} / \mathrm{m},\) the frequency is \(v\) \(=100 \mathrm{MHz}\). Find: (a) the efficient value of the displacement current density; (b) the mean energy flow density averaged over an oscillation period.
\(\begin{array}{lll}\text { 4.197. (a) } j_{d i s}=\pi \sqrt{2 \varepsilon_{0}} v E_{m}=0.20 & \mathrm{~mA} / \mathrm{m}^{2}\end{array}\) (b) \(\langle S\rangle=\) \(=1 / 2 \varepsilon_{0} c E_{m}^{2}=3.3 \mu \mathrm{W} / \mathrm{m}^{2}\)