The adjoining figure shows the variation of photo-current with anod...

The adjoining figure shows the variation of photo-current with anode potential for a photosensitive surface for three different radiations. Let \( I_{a}, I_{b} \) and \( I_{c} \) be the intensities and \( f_{a}, f_{b} \) and \( f_{c} \) be the frequencies for the curves \( a, b \) and \( c \) respectively. Then