How circular fringes are formed in Newton rings?

4.In a newtons ring set up the air film is enclosed below the convex lens. The thickness of the film is constant over a circle (or concentric circles) having center at the center of the lens. Hence the fringes are circular.

What are Newton’s rings explain?

Newton’s rings, in optics, a series of concentric light- and dark-coloured bands observed between two pieces of glass when one is convex and rests on its convex side on another piece having a flat surface. Thus, a layer of air exists between them. The figure shows contour patterns formed by various surfaces under test.

Why central ring is dark in Newton ring?

The central fringe in Newton’s rings is dark in the case of the reflected system because the air film thickness formed at the centre between the glass plate and the lens is zero. Hence, at the geometrical path difference between the incident and reflected rays from the glass plate is zero.

Where are these rings formed?

The rings are formed as a result of interference between light waves reflected from the upper and lower surfaces of the air film developed between the convex surface of plano convex lens and plane glass plate.

Which statement is true for Newton’s ring?

Statement I: Newton’s rings are formed in the reflected system when the space between the lens and the glass plate is filled with a liquid of refractive index greater than that of glass, the central spot of the pattern is dark.

Which lens is used for Newton’s ring experiment?

plano-convex lens
To study the formation of Newton’s rings in the air-film in between a plano-convex lens and a glass plate using nearly monochromatic light from a sodium-source and hence to determine the radius of curvature of the plano-convex lens. 1. Level the traveling microscope with its axis vertical.

How are rings of Newton’s lens formed?

The rings of Newton’s are formed as a result of interference which is between the light waves that are reflected from the top and bottom surfaces of the air film formed between the lens and glass sheet. The phenomenon of the formation of rings of Newton’s can be explained on the basis of the theory of wave of light that is:

What is the experimental setup for Newton’s Ring?

The experimental setup for Newton’s ring is shown in the figure above. The convex surface of a plano-convex lens having a long focal length (large radius of curvature) is placed in contact with a plane glass plate and clamped together.

Why do Newton’s rings appear rainbow colored in white light?

Newton’s rings seen in two plano-convex lenses with their flat surfaces in contact. One surface is slightly convex, creating the rings. In white light, the rings are rainbow-colored, because the different wavelengths of each color interfere at different locations.

What is the difference between Plano convex and Newton’s rings?

When a plano-convex lens lies on top of a plane lens or glass sheet, a small layer of air is formed between the two lenses. Newton’s rings are formed by the interference phenomenon when monochromatic and coherent rays of light are reflected from the top and bottom surfaces of this air film.