Question

Compare and contrast the pattern which is seen with two coherently illuminated narrow slits

Answer 1

In interference pattern, all the bright fringes are of same intensity. In diffraction pattern all the fringes are not of same intensity. The central fringe is the brightest and the intensity keeps decreasing for successive fringes.

In inteference the intensity of minimum is genreally zero or very small,and there is a good contrast between bright and dark fringes. In diffraction the intensity of minima is never zero and there is poor contrast between bright and dark fringes.

The width of interference fringes may or may not be equal. But the width of diffraction fringes is always unequal.