Question

What is a convex lens?​

Answer 1

a lens bound by two spherical surfaces bulging outwards and a single piece of glass that curves outward and converges the light incident on it are both convex lenses

Answer 2

The convex lens is a lens that converges rays of light that convey parallel to its principal axis (i.e. converges the incident rays towards the principal axis) which is relatively thick across the middle and thin at the lower and upper edges. The edges are curved outward rather than inward.