When the wavelength of radiation falling on a metal is changed from 500 nm to 200 nm, the maximum kinetic energy of the photoelectrons becomes three times larger. The work function of the metal is close to : [Main Sep. 03, 2020 (I)]
(a) 0.81 eV
(b) 1.02 eV
(c) 0.52 eV
(d) 0.61 eV