The graph shows the variation of photocurrent with anode potential for four different radiations. Let \mathrm{I}_{\mathrm{a}}, \mathrm{I}_{\mathrm{b}}, \mathrm{I}_{\mathrm{c}} and \mathrm{I}_{\mathrm{d}} are intensities and \mathrm{f}_{\mathrm{a}}, \mathrm{f}_{\mathrm{b}}, \mathrm{f}_{\mathrm{c}} and \mathrm{f}_{\mathrm{d}} be the frequencies for the curves \mathrm{a}, \mathrm{b}, \mathrm{c} and d respectively, then