Mirror questions

1. Dec 12, 2007

rhxoehwhfh

A concave mirror has a focal length of 26 cm. What is the radius of curvature of the mirror?

and also

The radius of curvature of a convex mirror is 60 cm. What is the focal length of the mirro?

Can anyone tell me the formula for finding each of the answer?...

2. Dec 12, 2007

Shooting Star

R has always the absolute value of 2f.

3. Dec 12, 2007

rhxoehwhfh

what is R and what is 2f , can you specify it for me please..

4. Dec 12, 2007

Shooting Star

R is the radius of curvature anf f is the focal length.

5. Dec 13, 2007

rhxoehwhfh

so formula for this is R=2f?

6. Dec 13, 2007

Yes.