photoelectric affect experiments are performer using ther different medal plates `p,q` and`r` having work function``phi_(p) = 2.0 eV, phi_(e) = 2.5 eV` and`phi_(r) = 3.0 eV` respectively A light beam containing wavelength of `550nm , 450 nm` and `350nm ` with equal intensities illuminates each of the plate . The correct `1 -V` graph for the experiment is` [Take hc = 1240 eV nm]`