Q 12-08-233NEETNEET 2022Top questionEasy
When light propagates through a material medium of relative permittivity $\varepsilon_r$ and relative permeability $\mu_r$, the velocity of light, $v$ is given by ($c$ - velocity of light in vacuum)
Answer: (A) $v = \dfrac{c}{\sqrt{\varepsilon_r \mu_r}}$
In a medium $v = \dfrac{1}{\sqrt{\mu\varepsilon}} = \dfrac{1}{\sqrt{\mu_r\mu_0\,\varepsilon_r\varepsilon_0}}$.
Since $c = \dfrac{1}{\sqrt{\mu_0\varepsilon_0}}$:
$$v = \frac{c}{\sqrt{\varepsilon_r\mu_r}}$$
Solution by Sreeraj P, M.Sc Physics