A photon of wavelength `4xx10^(-7)m` strikes on metal surface, the work function of the metal being 2.13 eV.
Calculate (1) the energy of the photon (eV).
(2) The kinetic energy of the emission.

Explanation

(1) Energy of a photon `(E)=hv=(hc)/(lamda)`
`=((6.626xx10^(-34)J*s)xx(3xx10^(8)m*s^(-1)))/(4xx10^(-7)m)` ltbgt `=4.97xx10^(-19)J`
or, energy of a photon`=(4.97xx10^(-19))/(1.602xx10^(-19))eV=3.10eV`.
(2) Kinetic energy of emitted electron
=energy of a photon-workfunction of a metal.
`=(4.97xx10^(-19)-2.13xx1.602xx10^(-19))J`
`=1.56xx10^(-19)J=0.97eV`