Question

The relation between electric field $E$ and magnetic field $H$ in electromagnetic wave is:

• A. $E=H$
• B. $E=\frac{{\mu }_0}{{\epsilon }_0}H$
• C. $E=\sqrt{\frac{{\mu }_0}{{\epsilon }_0}}H$
• D. $E=\sqrt{\frac{{\epsilon }_0}{{\mu }_0}}H$

Answer 1

The correct option is C $E=\sqrt{\frac{{\mu }_0}{{\epsilon }_0}}H$

In an em wave, electrical energy density is equal to magnetic energy density.

So, ${\epsilon }_o{E}^2/2=H^2/2{\mu }_o$
$E=\sqrt{\frac{{\mu }_o}{{\epsilon }_o}}H$