State the laws of refraction of light. If the speed of light in vacuum is `3 xx10^8` m/s, find the absolute refractive index of a medium in which light travels with a speed of `1.4 xx 10^8` m/s.

Explanation

Laws of refraction of light:
First law: The incident ray, the refracted ray, and the normal at the point of incidence all lie in the same plane.
Second law (Snell.s law): The ratio of sine of angle of incidence to the sine of angle of refraction is a constant for a given pair of media.
i.e., `(sin i)/(sin r) =` Constant
Speed of light in vacuum , `c = 3 xx 10^8 ` m/s
Speed of light in medium , `v = 1.4 xx 10^8 ` 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`