Notes

Refraction of Light …

Refraction of Light is the phenomenon in which the direction of propagation of an obliquely incident ray of light that enters the other medium, changes at the interface of the two media. Snell experimentally obtained the following laws of refraction:
(1) The Incident Ray, the refracted ray and the normal to the interface at the point of incidence, all lie in the same plane.
(2) The ratio of the sine of the angle of incidence to the sine of refraction is constant.
Remember that the angles of incidence
(1) and refraction (r) are the angles that the incident and its refracted ray make with the normal, respectively. We have,
sin i / sin r = n₂₁
where n₂₁ is a constant, called the refractive index of the second medium with respect to the first medium. We note that n₂₁ is a characteristic of the pair of media (and also depends on the wavelength of light), but is independent of the angle of incidence.