Question

Which of the following conditions is not necessary for a change in the direction propagation when a light ray goes from one medium to another? ​

Answer 1

Answer:

If the incident ray follows the normal drawn perpendicularly on the junction plane of 2 mediums, it will not refract. Angle of refraction (angle between the refracted ray and the normal), 'r' also becomes 0 thus no change in direction occurs.