Question

Ratio of average electric field $\left(E\right)$ to average magnetic field ($B$) is

• A. speed of light
• B. speed of oscillating particle
• C. electric field of $EM$ wave
• D. magnetic field of $EM$ wave

Answer 1

The correct option is A speed of light

Average electric field energy density (E)=$\frac{1}{2}{\in }_0{E}^2$ ...(1)
Average magnetic field density (B)= $\frac{1}{2{\mu }_0}{B}^2$ ....(2)
on putting (1)=(2)
$\frac{1}{2}{\in }_0{E}^2$=$\frac{1}{2{\mu }_0}{B}^2$
${\in }_0{E}^2=\frac{1}{{\mu }_0}{B}^2\therefore E=CB$
C = E/B