What is the difference between diffraction and interference of light?

I know these two phenomena but I want to know a little deep explanation. What type of fringes are obtained in these phenomena?

Answer

1. Two separate wave fronts originating from two coherent sources produce interference. Secondary wavelets originating from different parts of the same wave front constitute diffraction. Thus the two are entirely different in nature.


2. The region of minimum intensity is perfectly dark in interference. In diffraction they are not perfectly dark.


3. Width of the fringes is equal in interference. In diffraction they are never equal.


4. The intensity of all positions of maxima are of the same intensity in interference. In diffraction they do vary.

Diffraction pattern

Interference pattern