(i) Relation between diffraction from each slit to the interference Pattern in a double slit experiment :
(a) If slit width in interference Pattern is reduced to the size of wavelength of light used; the diffraction will also takes place along with interference.
(b) The diffraction pattern is itself due to the interference of wavelength belonging to same.
(ii) Waves diffracted from the edge of the circular obstacle interfere constructively at the centre of the shadow producing a bright spot.
