Question

Describe an expression for the radius of nth dark ring formed by reflection

Answer 1

Explanation:

When a Plano convex lens of large radius of curvature is placed on a flat glass plate , an air film is formed between lower surface of the lens and upper surface of the plate. Let R be the radius of curvature of lens surface. Let nth dark ring is obtained at point B. Let rn is the radius of nth dark ring.