Question

state the law of refraction of light explain the term absolute Refractive Index of a medium and write an expression to relate it with the speed of light in vacuum

Answer 1

Laws of Refraction
1.Snell Law of Refraction
The ratio between the values of the sine of angle of incidence and the sine of angle of refraction for two given optical media is a constant quantity.
2.The incident ray, the refracted ray and the normal lie in the same plane at the point of incidence.
The value of refractive index so obtained is called absolute refractive index.
Absolute refractive index = speed of light in vaccum/speed of light in optical medium

Answer 2

Explanation:

Snell's laws of refraction of light :

(1) : The incident ray, refracted ray and normal to the refracted surface lie in same plane.

(2) : Ratio of sine of angle of incidence in medium 1 to that of angle of refraction in medium 2 is equal to the ratio of refractive index of medium 2 to that of 1.

⟹

sinr

sini

=

n

2

n

2

Absolute refractive index of the medium is defined as the refractive index of that medium with respect to refractive index of vacuum i.e. ratio of refractive index of the given medium to that of vacuum.

Absolute refractive index of medium =

n

vacuum

n

medium

=

v

c

where v is the speed of light in that medium, c is the speed of light in vacuum