A ray of light passes from a medium X to another medium Y. No refraction of light occurs if the ray of light hits the boundary of medium Y at an angle of : (a) 0∘(b) 45∘ (c) 90∘ (d) 120∘
A light ray does not bend at the boundary in passing from one medium to the other medium if the angle of incidence is:
(a) 0∘(b)45∘(c)60∘(d)90∘
No refraction occurs when the light ray incident is ___ a boundary of two medium.