Question

define deflection of light

Answer 1

in easy words ...when light changes its direction after hitting surface of water or glass or any other thing...is called deflection

Answer 2

A deflection, in physics, refers to the change in an object's velocity as a consequence of contact (collision) with a surface or the influence of a field. Similarly when a ray of light falls on a plain surface, it's velocity changes and it is called deflection of light.