Newton's ring pattern in reflected system, viewed under white light consists of
A. Equally spaced bright and dark bands with central dark spot
B. Equally spaced bright and dark bands with central white spot
C. A few coloured rings with central dark spot
D. A few coloured rings with central white spot

Hint: Newton’s ring is a phenomenon in which we can see an interference pattern that also is created by reflection of light between two surfaces. Generally one of the surfaces is spherical and the other is an adjacent touching flat surface.

Complete step by step answer:
Generally when we do newton’s ring experiment we see that rings are actually fringes of equal thickness. We can see those rings when light is reflected from a plano-convex lens which has a long focal length and is placed in contact with a transparent glass plate. This occurs due to a thin air film that is formed between the plate and the lens. Now if we illuminate the lens plate system with a monochromatic beam of light falling on it generally normally, then concentric dark and bright interference rings are observed that also in reflected light. Now these circular fringes that were occurring were discovered by sir Isaac Newton and are therefore called Newton’s rings. Those rings are usually formed with equally spaced bright and dark bands consecutively with the central spot as a dark spot.

So, the correct answer is “Option A”.

Note: This phenomenon was first described and discovered by Robert Hooke in the book that he has written in 1664 named as Micrographia, then also its name is derived from the physicist Sir Isaac Newton, because he was the first man to analyse it.
There are two types of interferences:
1. Constructive Interference where light bright bands are formed.
2. Destructive interferences where dark bands are formed.