hich-statement-correctly-relates-the-focal-length-f-to-the-radius-of-curvature-r

Question

For a spherical concave mirror in the paraxial approximation, which statement correctly relates the focal length ff  to the radius of curvature RR?

Accepted Answer

f=R2\displaystyle f=\frac{R}{2}

Answer

f=Rf = R

Answer

f=2Rf = 2R

Answer

f=−R2\displaystyle f=-\frac{R}{2}