Question

If velocity of an electromagnetic wave in a medium is $3\times {10}^{8}m/s$ then find refractive index of medium.

• A. $1$
• B. $2$
• C. $0.5$
• D. $0.25$

Answer 1

The correct option is A $1$

We know that
$\mu =\frac{V_n}{V_m}$

When $\mu =$ refractive index of wave

$V_n=$ velocity of wave in vacuum

$V_m=$ velocity of wave in medium

Now, velocity of wave in vacuum $=3\times {10}^{8}m/s$

$\Rightarrow V_n=3\times {10}^{8}m/s$

velocity of wave in medium $=3\times {10}^{8}m/s$ (given)

$\Rightarrow V_m=3\times {10}^{8}m/s$

Hence, $\mu =\frac{3\times {10}^8}{3\times {10}^8}=1$

$\Rightarrow \mu =1=$ option $A$