Chapter 4, Problem 4.29P

Interpretation Introduction

Interpretation:

Kinetic energy has to be calculated if the surface of cesium metal is irradiated with light having wavelength of $\text{400}\text{nm}$.

Concept Introduction:

The minimum frequency of radiation that is required to eject an electron from metal is known as threshold frequency $({\nu }_0)$ of the metal.  This value differs for each and every metal.  Minimum energy that is required to eject an electron is $h{\nu }_0$.

Energy that is required in excess to eject an electron is given by the equation shown below.

    $E=h\nu -h{\nu }_0$

This excess energy is the kinetic energy of the electron that is being ejected.  Hence, the equation can be written as shown below.

    $E_k=h\nu -h{\nu }_0$