Why does'nt light bend when it falls perpendicularly on surface?(like glass slab)...Please explain with suitable diagram.

Asked by jgprmr | 17th Jun, 2017, 03:34: AM

Expert Answer:

If the incident ray falls on the glass slab perpendicularly or normally, it goes inside the slab un-deviated i.e there is no bending of light because of the following reasons:

As the incident rays passes along the normal to the surface, the angle of incidence becomes zero.
It is a known fact that angle of incidence and the angle of refraction are related to each other and are governed by Snell's Law i.e
 
begin mathsize 12px style Refractive space Index equals fraction numerator Sin space straight i over denominator Sin space straight r end fraction
Refractive space Index cross times Sin space straight r equals Sin space 0
Refractive space Index cross times Sin space straight r equals 0
As space Refractive space Index not equal to 0 comma space
Sin space straight r equals 0
straight r equals 0 degree end style
This explains why the angle of refraction is zero when the incident light falls normal or perpendicular to the glass slab.
 

Answered by Abhijeet Mishra | 17th Jun, 2017, 01:56: PM