# Question c2c4a

Dec 1, 2017

There is no derivation of photoelectric effect equation. There is just an understanding by interpreting Planck's quanta as light particle.

#### Explanation:

The energy of a photon is related to its frequency as : ${E}_{\setminus \nu} = h \setminus \nu$;

The electron is bound to the surface and some energy is required to pluck this electron. This energy is called work function ($\setminus \phi$). This energy corresponds to a photon of frequency $\setminus {\nu}_{0}$.
$\setminus \phi = h \setminus {\nu}_{0}$

If a photon with frequency less than $\setminus {\nu}_{0}$ is incident on the material, no photo electrons will be produced. However if a photon with frequency greater than $\setminus {\nu}_{0}$ is incident on the surface, an energy of $\setminus \phi = h \setminus {\nu}_{0}$ will be utilised in plucking the electron and the remaining will become the kinetic energy of the electron.

h\nu = \phi + E_k; \qquad h\nu = h\nu_0 + E_k;#
Kinetic energy of the ejected photo electron is:

${E}_{k} = h \setminus \nu - h \setminus {\nu}_{0} = h \left(\setminus \nu - \setminus {\nu}_{0}\right)$

This is the photoelectric equation which was a mystery and could not be explained using classical electrodynamics. Einstein gave a simple explanation by interpreting Planck's photons as light particles.