Question

In a plane electromagnetic wave, the amplitude of the magnetic field is $5.0\times {10}^{-6}T$. Find the amplitude of the electric field and the total average energy density of the wave.

Answer 1

$E=Bc$

$=5\times {10}^{-6}\times 3\times {10}^8$

$=1.5\times {10}^{3}V{m}^{-1}$

Energy density =$\frac{1}{2{\mu }_0}{B}^2$

$=\frac{1}{2\times 4\pi \times {10}^{-7}}\times (5\times {10}^{-6}{)}^2$

$=1.0\times {10}^{-5}J{m}^{-3}$ (approx)