Question

If the ratio of relative permeability and relative permittivity of a uniform medium is $1 : 4$. The ratio of the magnitudes of electric field intensity ($E$) to the magnetic field intensity ($H$) of an EM wave propagating in that medium is:
$\text{Given that } \sqrt{\frac{\mu_0}{\epsilon_0}} = 120 \pi :$

• A. $30\pi : 1$
• B. $1 : 120\pi$
• C. $60\pi : 1$
• D. $120\pi : 1$

Answer 1

Answer: (C)

$60\pi : 1$

Answer 2

In an electromagnetic wave, the ratio of electric field intensity (E) to magnetic field intensity (H) in a medium is given by:

$\frac{E}{H} = \sqrt{\frac{\mu}{\epsilon}} = \sqrt{\frac{\mu_r \mu_0}{\epsilon_r \epsilon_0}} = \sqrt{\frac{\mu_0}{\epsilon_0}} \sqrt{\frac{\mu_r}{\epsilon_r}}$

Given that $\sqrt{\frac{\mu_0}{\epsilon_0}} = 120\pi$ and $\frac{\mu_r}{\epsilon_r} = \frac{1}{4}$:

$\frac{E}{H} = 120\pi \sqrt{\frac{1}{4}} = 60\pi$

Thus, the ratio of E to H is 60π : 1.