Suppose that the electric field part of an electromagnetic wave in vacuum is $E=\{(3.1$ $\left.\mathrm{N} / \mathrm{C}) \cos \left[(1.8 \mathrm{rad} / \mathrm{m}) \mathrm{y}+\left(5.4 \times 10^{6} \mathrm{rad} / \mathrm{s}\right) \mathrm{t}\right]\right\}^{\wedge} \mathrm{i}$
(a) What is the frequency v?
(b) What is the amplitude of the magnetic field part of the wave?

3 years ago

(a) Frequency is calculated as

$v=\omega / 2 \pi=5.4 \times 10^{6} /(2 \times 3.14)=0.859 \times 10^{6} \mathrm{~Hz}$

(b) Amplitude of the magnetic field can be calculated as
$B_{o}=\frac{E_{o}}{c}$
$=3.1 /\left(3 \times 10^{8}\right)=1.03 \times 10^{-8} \mathrm{~T}=10.3 \times 10^{-9} \mathrm{~T}=10.3 \mathrm{nT}$