CBSE Class 12-science Answered

Interference is the phenomenon of waves where waves from two different coherent sources superimpose at a given point and creates fringes.

The phenomenon of bending of light around the corners of an opaque object which obstructs the path of light is called diffraction.

It is due to diffraction we don’t see sharp shadows of objects; instead we see a penumbra region surrounding the umbra region of the shadow. Umbra is the darkest part of the shadow while penumbra is the part of the shadow which is partially illuminated.

Difference between interference and diffraction:

In interference pattern the intensity of dark fringe is completely zero. In diffraction pattern the intensity of secondary minima is minimum, but not completely zero.

In interference pattern the width of all the interference fringes is equal. In diffraction pattern the width of central maxima is large, and on increasing distance , the width of maxima decreases.

In interference pattern the intensity of all the bright bands is equal. In diffraction pattern the intensity of all the secondary maxima is not equal.