Question

Assertion: 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 bright.
Reason: This is because the reflection in these cases will be from a denser to rarer medium and the two interfering rays are reflected under similar conditions.

A) If both assertion and reason are true but the reason is the correct explanation of assertion.
B) If both assertion and reason are true but the reason is not the correct explanation of assertion.
C) If the assertion is true but reason is false.
D) If both the assertion and reason are false.
E) If reason is true but assertion is false.

Answer 1

Hint : During a formation of Newton's ring , Parallel beams of monochromatic light are usually incident on Plano-convex lenses and glass plates. Part of each incident light rays are reflected from the lower surface of the lenses and a part, after refraction through the film between the lens and the plate, is reflected back from the surface of the glass plate.

 Complete step by step solution: The term "Newton's rings" refers to a ring in contact with a glass of a planar surface formed by a curved, usually convex lens glass. The curved glass, which is kept in the plan glass, forming an air film between them, grows larger and larger along the curve. When light is directed at a curved glass, many concentric circles appear. That is why the rings are called Newton's rings.

Hence, option A is correct.

Additional Information: A "Newton ring" is a ring formed by the contact of curved glass, usually a convex lens, with flat glass. The curved glass, which is held on flat glass and forms a film of air between them, is getting larger and larger along the length of the curve. When the light is directed at the curved glass, many concentric circles appear. The formed Newton ring is usually a phenomenon in which dark and bright objects alternate, with the dark areas starting in the center. It is formed as a result of interference between the light reflected by the two surfaces. For applications, Newton Rings can be used by lens manufacturers to check the quality of their lenses. For a good lens, the ring should be uniform, Named after Sir Isaac Newton, who first studied in 1717, Newton Ring is a pattern of interference caused by two surfaces (planes adjacent to the sphere surface) after light reflection.

Note: When viewed in monochromatic light, it appears as a series of alternating luminous and dark rings centered at the point of contact between the two surfaces. When viewed with white light, light of different wavelengths interferes with different thicknesses of layers between surfaces, creating a rainbow-colored concentric ring pattern.