Problem 5.28

A point source with luminous intensity \(I_{0}=100 \mathrm{~cd}\) is positioned at a distance \(s=20.0 \mathrm{~cm}\) from the crest of a concave mirror with focal length \(f=25.0 \mathrm{~cm} .\) Find the luminous intensity of the reflected ray if the reflection coefficient of the mirror is \(\rho=0.80\)