What is the relation between the focal length and radius of curvature of a spherical mirror (concave mirror or convex mirror)? Calculate the focal length of a spherical mirror whose radius of curvature is 26 cm.
For a spherical mirror the principal focus (F) lies exactly mid-way between the pole (P) and centre of curvature (C). So, the relation between focal length (f) of a spherical mirror and radius of curvature (R) is
f=R/2
Radius of curvature (R) = 26cm
Focal length (f) =?
We know that
f=R/2
=26/2
f =13cm