Question

What is a work function?

Answer 1

Hint: We need to understand the usage of the term work function in a physical way and then find the phenomenon associated with the work function to understand what actually it means and thereby provide the solution for the given problem.

Complete answer:
The work function is the characteristic property of a metal which is often used in the photoelectric effect. We know that the photoelectric effect is the phenomenon in which the photons of energy greater than a particular value ionises an atom creating a free electron.
The electron emission is possible only if the energy of the incident photons is greater than a threshold value. We know that this threshold energy is directly related to the threshold frequency of the electron. In other words, the electron emission requires the incidence of photons of a minimum frequency known as the threshold frequency.
i.e.,
\[{{\phi }_{0}}=h\nu \]
Where the minimum required energy is given as \[{{\phi }_{0}}\], which is known as the work function of the metal.
The work function is the minimum energy required by a photon to emit electrons from the metal which is the ionization energy of the metal itself. Any energy provided greater than the work function will contribute to the kinetic energy of the emitted electrons. The work function is dependent on the chosen metal and is independent of the intensity of the photon incident on the metal.
This is the required solution.

Note:
The work function of a metal is the characteristic property of the material. It is the minimum energy required to ionise an electron from its valence shell. This energy can be provided by any means – optical, thermal or electric energies – in different methods.