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

An observer can see through a pinhole,the top end of a thin rod of height $h$,placed as shown in the figure. The beaker's height is $3h$ and its radius is $h$. When the beaker is filled with a liquid up to a height $2h$,he can see the lower end of the rod. Then the refractive index of the liquid is

$A$ light ray is incident on a spherical glass surface at an angle $\alpha$ and is refracted at an angle $\beta$. What is the angle of deviation between the emergent ray and the incident ray?

If $\varepsilon_{0}$ and $\mu_{0}$ are the permittivity and permeability of free space and $\varepsilon$ and $\mu$ are the corresponding quantities for a medium,then the refractive index of the medium is:

$A$,$B$ and $C$ are parallel-sided transparent media of refractive indices $n_{1}$,$n_{2}$ and $n_{3}$ respectively. They are arranged as shown in the figure. $A$ ray is incident at an angle $i$ on the surface of separation of $A$ and $B$. After refraction into medium $B$,the ray grazes the surface of separation of media $B$ and $C$. Then,$\sin i$ equals to

As shown in the figure,after passing through medium $1$,the speed of light $v_{2}$ in medium $2$ will be $..... \times 10^{8} \, ms^{-1}$. (Given $c = 3 \times 10^{8} \, ms^{-1}$)