Question

Write laws of refraction of light. Explain the same with the help of ray diagram, when a ray of light passes through a rectangular glass slab.

Answer 1

Laws of Refraction of light

First law:- The incident ray, the refracted ray and the normal to the interface of two transparent media at the point of incidence, all lie in the same plane.

Second law:- (Snell's law) The ratio of sine of angle of incidence (i) to the sine of angle of refraction (r) is a constant ,for a light of constant wavelength and a given pair of media i.e. $\frac{\sin i}{\sin r}=constant=\mu$

here,$\mu$ is refractive index.

In the above figure, A is point of incidence. BA is incident ray. AC if refracted ray. $N{N}^{{}^{\prime }}$ is normal to interface. $i$ is angle of incidence. $r$ is angle of refraction & snell's law states that

$\frac{\sin i}{\sin r}$ = constant = Refractive index