Ray Optics Question 11
Question 11 - 31 January - Shift 1
In a medium the speed of light wave decreases to 0.2 times to its speed in free space The ratio of relative permittivity to the refractive index of the medium is $x: 1$. The value of $x$ is
(Given speed of light in free space $=3 \times 10^{8} m s^{-1}$ and for the given medium $\mu_r=1$ )
Show Answer
Answer: (5)
Solution:
Formula: Refractive Index
$ V=\frac{C}{\mu} \Rightarrow \mu=\frac{C}{V}=\frac{C}{0.2 C} $
$\mu=5$
$\mu=\sqrt{\epsilon_r \mu_r}$
$\Rightarrow \in_r=\frac{\mu^{2}}{\mu_r}$
$\therefore \frac{\epsilon_r}{\mu}=\frac{\mu}{\mu_r}=5$
