**(i)** Energy (E) = \(\frac{hv}{\lambda}\); h = 6.6 × 10^{−34}Js

C = 3 x 10^{8} ms^{-1}

E = \(\frac{6.6\times10^{-34}Js\times3\times10^8m}{4\times10^{-7}m}\)

= 4.97 × 10^{−19} J

= \(\frac{4.97\times10^{-19}J}{1.602\times10^{-9}}\)

= 3.10 eV.

Energy of the photon in eV = 3.10

**(ii)** Kinetic energy of the emission of photo-electrons (K.E)

= hv − \(\omega_o\)(where \(\omega_o\) = work function)

= 3.10 eV − 2.13 eV = 0.97 eV.