Question

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

Answer 1

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

Answer 2

But what does it mean? Why is it important?

Answer 3

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

Answer 4

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

Answer 5

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

Answer 6

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

Answer 7

Okay. Sweet. Thanks.

Answer 8

You're welcome :)