Wavelength of the photon, λ = 4 x 10^{-7} m

Work function of the metal, W = 2.13 eV = 2.13 x 1.6020 x 10^{-19} J

= 3.14 x 10^{-19} J

(i) Energy of photon = ch/λ = {3 x 10^{8} ms^{-1} x 6.626 x 10^{-34} Js}/{4 x 10^{-7} m}

= 4.97 x 10^{-19} J

= {4.97 x 10^{-19} J}/{1.6020 x 10^{-19} J/eV} = 3.10 eV

(ii) Kinetic energy of the emission = E_{photon} - W

= 4.97 x 10^{-19} J - 3.41 x 10^{-19} J

= 1.56 x 10^{-19} J

= 3.10 eV - 2.13 eV = 0.97 eV

(iii) Kinetic energy of the emitted photoelectron = 1/2 m x v^{2}

or,