Question

Write four differences between interference and diffraction.

Answer 1

Hint: In order to get the difference you need to know that interference is the phenomena in which the two or more electromagnetic waveforms combine to form a resultant wave in which the amplitude is either increased or decreased. Diffraction is the phenomena in which the light waves strikes with an obstacle or slit and changes its direction which results in the formation of alternative bright and dark spots.

Complete step-by-step answer:

Interference:-

1. When the two light rays from the coherent sources are superimposed interference fringes are formed.
2. In interference all the bright fringes have the same intensity.
3. All the fringes in interference are of the same width.
4. In interference the fringes can be distinguished easily by distinguisher since dark is full dark and bright has good intensity.

Diffraction:-

1. Only one light source in present and fringes are formed due to superposition of waves from the same source.
2. The center most fringe is the brightest one while other fringes have intensity in decreasing order.
3. In diffraction the width of the fringe is not the same it decreases when we move from center to the other sides.
4. The dark fringes are not perfectly darker in diffraction so differentiating among the fringes here is not that easy like in interference.

Note: Interference of light is a special phenomenon that reflects the wave existence of light. Due to the interference of light, two waves interact with each other and where crest and crest or trough and trough cross the amplitude of light is very high and, we say, positive interference occurs. Diffraction refers to a number of phenomena that arise when a wave meets an obstacle or a slit. It is defined as a bending of waves around the corners of an obstacle or through an opening into the geometric shadow region of an obstacle / aperture.