Question

What are the laws of refraction?

Answer 1

1. The incident ray, the refracted ray and the normal all lie in the sameplane.            2.the angle of incidence is not equal to angle of refraction.it depends on the medium used.the   ratio of the sine of the angle of incidence to the sine of the angle of refraction is a const ie μ=sine i/sine r

Answer 2

See the diagram.

There are two laws.

1.  The incident ray from medium 1, the perpendicular at the point of incidence of ray on the boundary between two media ,  and the refracted ray in the medium 2 are all coplanar.  

2.  The ratio of  Sine of angle of incidence i  to the Sine of angle of refraction r is constant.

$\frac{Sin i }{Sin r}= \mu_{21}=\frac{\mu_2}{\mu_1}\\\\\mu_1\ Sin\ i = \mu_2\ Sin\ r\\\mu=refractive\ index$
 
    When the medium 2 is optically denser than medium 1, the refracted ray bends towards the normal at the point of incidence.  When medium 2 is less denser than medium 1, then the ray bends away from the normal.