Question

How is refractive index of a medium 2 given with respect to medium 1 related to speed of light?
where, $n_1$ and $n_2$ are the respective refractive indicies of medium 1 and medium 2. And, $c_1$ and $c_2$ are speed of light in medium 1 and medium 2 respectively.

• A. $n_{21}$ = $\frac{v_2}{v_1}$
• B. $n_{21}$ = $\frac{v_1}{v_2}$
• C. $n_1$ - $n_2$ = $v_2$ - $v_1$
• D. None of these

Answer 1

The correct option is B

$n_{21}$ = $\frac{v_1}{v_2}$

The refractive index of medium 2 with respect to medium 1 is given by the ratio of speed of light in medium 1 and speed of light in medium 2.

So, $n_{21}$ = $\frac{v_1}{v_2}$