When a biconvex lens of glass of refractive index 1.5 is dipped in a liquid, it acts like a plane sheet of paper. This means the refractive index of the liquid is
To understand why the biconvex lens of glass with a refractive index of 1.5 behaves like a plane sheet of paper when dipped in a liquid, we must consider the behavior of light as it passes through different mediums and the concept of the refractive index. The refractive index (or index of refraction) of a material determines how much the speed of light is reduced inside the material. When light moves from one medium to another, it bends at the interface between the two materials. This phenomenon is described by Snell's law: n1sin‌(θ1)=n2sin‌(θ2) where: n1 (n_1) is the refractive index of the first medium, n2 (n_2) is the refractive index of the second medium, θ1(θ−1) is the angle of incidence, and θ2(θ_2) is the angle of refraction. When the refractive index of the liquid is equal to that of the glass ( 1.5 in this case), the lens will not bend the light rays as they pass from the glass to the liquid. Therefore, the lens will no longer converge or diverge light; it will act as though it were a plane sheet of glass with no curvature. Thus, for the biconvex lens to behave as a plane sheet of paper, the refractive index of the liquid must be equal to that of the glass. Hence, the correct answer is: Option C: Equal to that of glass