Question

Monochromatic light is refracted from air into glass of refractive index $\mu$. The ratio of the wavelengths of incident and refracted waves is

• A. $1:\mu$
• B. $1:{\mu }^2$
• C. $\mu :1$
• D. ${\mu }^2:1$

Answer 1

The correct option is C $\mu :1$

We know that
$\lambda \propto \frac{1}{\mu }$
$\Rightarrow {\lambda }_1=\frac{k}{{\mu }_1}--\left(i\right)and{\lambda }_2=\frac{k}{{\mu }_2}--\left(ii\right)$
where${\mu }_1$ is the refractive index of air and ${\mu }_2$ is the refractive index of glass
From (i) and (ii),
${\lambda }_1{\mu }_1={\lambda }_2{\mu }_2\Rightarrow \frac{{\lambda }_1}{{\lambda }_2}=\frac{{\mu }_2}{{\mu }_1}=\mu :1$