Question

If the speed of light in material $A$ is $1.25$ times its speed in material $B$, then the ratio of the refractive indices of these materials is

• A. $1.50$
• B. $1.00$
• C. $0.800$
• D. $1.25$
• E. $0.90$

Answer 1

The correct option is C $0.800$

For two media
$\frac{{\mu }_1}{{\mu }_2}=\frac{v_2}{v_1}$
$\frac{{\mu }_1}{{\mu }_2}=\frac{1}{1.25}$
$\frac{{\mu }_1}{{\mu }_2}=0.800$