Question

N. When light passes sharp edges or goes through narrow slits the rays are deflected and produce fringes of light and dark bands

Answer 1

due to the wave nature of light when light passes sharp edges or goes through narrow slits, at some places the light waves undergoes successive superposition and at some places these waves products distructive superposition. The places of successive superposition appears to be bright fringes and the places of distructive superposition appears to be dark fringes.