4. When electromagnetic radiation of wavelength 300 nm falls on the surface of a metal, electrons are emitted with the kinetic energy of 1.68 105 J mol-1. What is the minimum energy needed to remove an electron from the metal? (h 6.626 10-34 Js, c = 3 108 ms-1, NA = 6.022 1023 mol-1) [NEET-2022 (Phase-2)] (1) 2.31 105 J mol-1 (3) 3.84 104 J mol-1 (2) 2.31 106 J mol-1 (4) 3.84 10-1 J mol-1 11