Question

Cathode of photoelectric cell is changed such that the work function changes from ${W_1}$ to ${W_2}$ $\left( {{W_1} < {W_2}} \right)$. If the current before and after changes are ${I_1}$ ​ and ${I_2}$​ all other conditions remaining unchanged, then (assuming $h \nu > {W_2}$).
$\left( A \right){I_1} = {I_2}$
$\left( B \right){I_1} < {I_2}$
$\left( C \right){I_1} > {I_2}$
$\left( D \right){I_1} > 2{I_2}$

Answer 1

When a light incident on a surface of a metal causes the electrons to eject and their kinetic energy can be determined in the photoelectric effect.
Due to emission of electrons, photocurrent is formed. Now find the relation between the current and the work function to answer the following question.

Complete answer:
In the photoelectric process, the electron emitted is called the photoelectron.
When a light is incident on a surface of a metal causes the electrons to eject and their kinetic energy can be determined in the photoelectric effect.
Due to emission of electrons, photocurrent is formed.
The difference between photon energy and the binding energy of the electron give the kinetic energy of an electron ejected.
The material will have maximum kinetic energy when the electron is directly emitted from the surface.
Certain energy is required to eject electrons from a metal surface. The energy is known s the work function.
Photocurrent is independent of the work function.
But it is dependent on the intensity of the incident rays. Hence the current will remain the same even after changing the values of the work function. So, we can write ${I_1} = {I_2}$

Hence Option A is the correct option.

Note: Photoelectric effect is caused when a light falls on the surface. It is used in studying the electron energy levels in the matter.
Kinetic energy is maximum when affected by two factors that are the frequency of the incident radiation and the material on the surface.
The minimum energy required to liberate from the surface is called the work function.