When Monochromatic Radiation of Energy 21

When monochromatic radiation of energy 21.22 eV from a helium lamp is used to irradiate a sample of nitrogen, N₂, gas in a photoelectron spectrometer, electrons are ejected with a maximum kinetic energy of 1.41 * 10⁶ m s^-1. Calculate the molar ionization energy of N₂.

A) 4.13 * 10³ kJ mol^-1
B) 2.60 *10³ kJ mol^-1
C) 15.5 kJ mol^-1
D) 1.50 * 10³ kJ mol^-1