What is responsible for the light rays coming together at the focal point?

Focal point is a point where reflected or refracted rays come together at one point. Convex mirror works such that it reflects rays of light through a point called the focal point. The principle is based on the fact that the rays that are parallel to the principle focus of a convex mirror are reflected such that the meet at a point called focal point.

Sorry my friend i don't know the answer. i am just in 6th