Newton’s rings are visible when a planoconvex lens is placed on a flat glass surface. For a particular lens with an index of refraction of n = 1.50 and a glass plate with an index of n =1.80, the diameter of the third bright ring is 0.640 mm. If water (n = 1.33) now fills the space between the lens and the glass plate, what is the new diameter of this ring? Assume the radius of curvature of the lens is much greater than the wavelength of the light.

Newton’s rings are visible when a planoconvex lens is placed on a flat glass surface. For a particular lens with an index of refraction of n = 1.50 and a glass plate with an index of n =1.80, the diameter of the third bright ring is 0.640 mm. If water (n = 1.33) now fills the space between the lens and the glass plate, what is the new diameter of this ring? Assume the radius of curvature of the lens is much greater than the wavelength of the light.