Question

Velocity of light in glass, whose refractive index with respect to is $1.5$, is $2\times {10}^{8}m/s$. In a certain liquid the velocity of light is found to be $2.5\times {10}^{8}m/s$. The refractive index of liquid with respect to air is:

• A. $0.64$
• B. $0.80$
• C. $1.20$
• D. $1.44$

Answer 1

The correct option is C $1.20$

As we know,

$\mu \propto \frac{1}{v}\Rightarrow \frac{{\mu }_1}{{\mu }_2}=\frac{v_g}{v_l}\Rightarrow \frac{{\mu }_1}{1.5}=\frac{2\times {10}^8}{2.5\times {10}^8}\Rightarrow {\mu }_1=1.2$