Question

State the laws 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

1st law: the incident ray, refracted ray and normal to the interface at the point of incidence lie in the same plane.

2nd law: The sine of angle of incidence bears a constant ratio with sine of angle of refraction for a given pair of media. Or sini/sinr =constant

Absolute Refractive Index of a medium = Speed of light in air or vacuum/Speed of light in the medium.