Question

Stopping potential and experiment of photoelectric effect is 1.5 volt what is the maximum kinetic energy of photoelectrons emitted

Answer 1

Given:

Stopping potential in an experiment of photoelectric effect is 1.5 volt.

To find:

Max kinetic energy of the emitted electrons ?

Calculation:

So, in photoelectric effect , when photons of adequate energy (greater than threshold value) strike on a metal surface electrons are emitted with a certain kinetic energy.

Now, if an opposite potential difference is applied it is seen that the electrons stop due to the opposing force.

Now, when it is said that the STOPPING POTENTIAL is 1.5 Volts, it means that it this amount of potential difference is required to stop the most active electron emitted from the metal surface.

$\rm \therefore \: (KE)_{max} = e \times V$

$\rm \implies \: (KE)_{max} = e \times 1.5$

$\rm \implies \: (KE)_{max} = 1.5 \: eV$

So, the electrons with the maximum kinetic energy is 1.5 eV.

• Please note that if the value of electron charge is put in the equation, then the energy unit should be in JOULES.