Question

How corpuscular theory failed to explain refraction.?

Answer 1

Corpuscular theory predicted that if the ray of light (on refraction) bends towards the normal then the speed of light would be greater in the second medium. But the experiment of Foucault proved that, on refraction if the light bent toward the normal, then the speed of light will be lesser in the second medium. Thus, Corpuscular Theory didn't satisfactorily explain refraction. But, reflection is said to be explained by this theory.

In case of reflection practically, when the light ray is incident at an angle zero with respect to the normal drawn at the interface, ray bounce back in the same direction with the angle of reflection zero. According to Corpuscular model, if corpuscle bounce back in the same direction (when angle of incidence is zero) it came from, there will be collisions with the corpuscles which are going to be incident later. Then, there will be random displacement of corpuscles.

Reference https://www.physicsforums.com/threads/didnt-newtons-corpuscular-theory-fail-to-explain-reflection.752245/