GENERAL KNOWLEDGE

Detailed explanation-1: -The central spot of Newton’s rings is dark when the medium between plano convex lens and plane glass is rarer than the medium of lens and glass. The central spot is dark because the phase change of is introduced between the rays reflected from surfaces of denser to rarer and rarer to denser media.

Detailed explanation-2: -Newton’s rings in transmission So the transmitted rays near the point of contact have constructive interference in transmission. So, in a Newton’s rings pattern in transmission are like negative images of those seen in reflection: a bright patch at the centre followed by a dark ring, then a bright, etc.

Detailed explanation-3: -These reflected rays get superimposed and form an interference pattern in the form of a ring called Newton’s ring. The central ring is dark and then alternate dark and bright rings are formed as shown in the figure alongside. These rings are formed due to the superposition of the reflected beam of light.

Detailed explanation-4: -A bright centre in reflected system can be obtained by selecting lens, medium and the glass plate in such a way that refractive index of lens is less than the medium and refractive index of medium is less than the plate.

Detailed explanation-5: -Hence, in an interference experiment, monochromatic light is replaced by white light, we will see a few colored bands and then uniform illumination.