State the laws of refraction of light. If the speed of light in vacuum is `3xx10^(8)` m/s, find the absolute refractive index of a medium in which light travels with a speed of `1.4xx10^(8)` ms?

Explanation

(i) There are two laws of refraction
a. The ratio fo the sine of the angle of incidence to the sine of the angle of refractive is constant. This is known as Snell.s law. Mathematicaly, it can be expressed as
`sini//sin r=n_(12)`
Here `n_(12)` is the relative refractive index of medium 1 with respect to medium 2.
b. The incident ray, the refracted ray and the normal to the interface of two media at the point of incidence lie on the same plane.
(ii) Give `c=3xx10^(8)m//s`
`v=1.4xx10^(8)m//s`
Absolute refractive index
`=("Speed of light in vacuum")/("Speed of light in medium")`
`=(3xx10^(8)m//s)/(1.4xx10^(8)m//s)=2.14`