Question

 State Huygen’s principle. Using this principle explain how a diffraction pattern is obtained on a screen due to a narrow slit on which a narrow beam coming from a `=> n = (vlamda)/(vlamda_omega)`monochromatic source of light is incident normally.

Answer 1

Huygen’s Principle

It states that

(i) Rays (light rays) are perpendicular to wave fronts.

Where wave fronts are defined as a surface of constant phase.

(ii) The time taken for light to travel from one wave front to another is same along any ray.

Diffraction Pattern:

Explanation of diffraction phenomena along with the following diagrams.