Which has more power : a thick convex lens or a thin convex lens, made of the same glass? Give reason for your choice.

A thick convex lens has more power than a thin convex lens because it has greater curvature or lesser focal length than a thin lens. 

Explanation

A thick convex lens has greater curvature or lesser focal length, whereas a thin convex lens has lesser curvature or greater focal length. 

We know that the power of the lens is inversely proportional to the focal length of the lens. Hence, the lens with a shorter focal length will have more power or higher refraction (causes more bending of light rays). While the lens with a longer focal length will have less power or low refraction (causes less bending of light rays).

Thus, a thick convex lens has more power, as it has a lesser focal length.