The two laws of refraction of light are: The incident ray, the refracted ray and the normal to the refracting surface at the point of incidence all lies in the same plane. The ratio of sine of angle of incidence of the sine of the angle of refraction is a constant for a given pair media i.e
Sin.i /Sin.r = constant
The Laws of Refraction with Examples
The Laws of Refraction
- Incident ray, reflected ray, refracted ray and the normal of the system lie in the same plane.
- Incident ray, coming from one medium to the boundary of another medium, is refracted with a rule derived from a physicist Willebrord Snellius. He found that there is a constant relation between the angle of incident ray and angle of refracted ray. This constant is the refractive index of second medium relative to the first medium. He gives the final form of this equation like;
Where n1 is the refractive index of first medium and n2 is the refractive index of second medium, v1 is the speed of light in firs medium and v2 is the speed of light in second medium.
Example: Find the velocity of the ray in a medium having refractive index 2.
Example: A ray coming from medium X is refracted as shown in the figure below while passing to the medium Y. Find ratio of the refractive indexes of the mediums. (sin37º=0, 6 and sin53º=0, 8)