The speed of light in a medium of refractive index $1.25$ is . . . . . . .
(Speed of light in vacuum is $3 \times 10^{8} \,m \,s^{-1}$)

If the speed of light in vacuum is $C \ m/s$,then what is the velocity of light in a medium of refractive index $1.5$?

When light enters glass from vacuum,then the wavelength of light:

$A$ fish rising vertically up towards the surface of water with speed $3 \; ms^{-1}$ observes a bird diving vertically down towards it with speed $9 \; ms^{-1}$. The actual velocity of the bird is.......$ms^{-1}$ (Assume refractive index of water $\mu = 4/3$).

When a ray of light of frequency $6 \times 10^{14} \ Hz$ travels from water of refractive index $4/3$ to glass of refractive index $8/5$,its

$A$ light ray enters a solid glass sphere of refractive index $\mu=\sqrt{3}$ at an angle of incidence $60^{\circ}$. The ray is both reflected and refracted at the farther surface of the sphere. The angle (in degrees) between the reflected and refracted rays at this surface is......