A spherical air bubble is embedded in a piece of glass. For a ray of light passing through that bubble, the bubble behaves like a

A spherical air bubble embedded in glass behaves optically like a converging lens (option A). The curved surfaces of the bubble act as refracting surfaces, bending light rays passing through them. Specifically, because the refractive index of the glass is higher than that of the air inside the bubble, light entering the bubble bends towards the normal at each interface. This refraction causes the rays to converge towards a focal point, much like how a convex lens focuses light. The position of this focal point depends on the curvature of the bubble’s surfaces and the refractive indices involved. Therefore, when light passes through the spherical air bubble in the glass, it undergoes convergence due to the lens-like optical behavior of the bubble, focusing incoming light rays towards a central point. This characteristic makes the spherical air bubble functionally akin to a converging lens in optical applications and experiments involving refraction and focusing of light.