Question

The minimum energy necessary to overcome the attractive force between the electron and the surface of the silver metal is $7.52\times {10}^{-19}$ J. What will be the maximum kinetic energy of the electrons ejected from silver which is being irradiated with ultraviolet light having a wavelength $360\mathring{A}$?

Answer 1

Minimum energy required to overcome attractive forces between electron and metal is the work function of the metal, i.e. $W=7.52\times {10}^{-19}J$

$E=\frac{hc}{\lambda }=20.89\times {10}^{-19}J$ is the energy of the incident ultraviolet light.

Kinetic energy of the emitted photoelectron is given by,

$K.E_{max}=E-W$

$K.E_{max}=20.89\times {10}^{-19}J-7.52\times {10}^{-19}J$

$K.E_{max}=13.37\times {10}^{-19}J$