What is "meant" by the focal length of a concave mirror?

Question

anonymous · Answer

I understand that the focal length is the distance from the focal point to the center of the surface of the mirror.

anonymous · Answer

But what does it mean? Why is it important?

anonymous · Answer

It is the point where light rays from anywhere infinitely far and close and parallel to the central point converge.

anonymous · Answer

which means, rays can be focused onto one point, like radio parabolic dishes.

anonymous · Answer

Okay. So light rays always converge for a concave mirror? Is it any different for a convex mirror? Do they diverge?

anonymous · Answer

yes, a point source of light rays located on the convex mirror will have it's light rays become parallel to the central axis..

anonymous · Answer

Okay. Sweet. Thanks.

anonymous · Answer

You're welcome :)