AAI ATC Junior Executive 2016 Shift 1 Paper

A light beam is incident on a metal target with a work function of 2.3 eV. If a stopping potential of 1.3 eV is required, what is the wavelength of the incident light? (h = 6.63 × 10^-34 J s, c = 3 × 10⁸ m/s, 1 eV = 1.6 × 10^-19 J):