Question

State the energy conversion taking place in a solar cell.

Answer 1

Hint: A solar cell is a device or setup which is used to convert solar energy into electrical energy. It is also called a photovoltaic cell. It is based on the phenomenon of photoelectric emission of electrons. These electrons give rise to photocurrent.

Complete answer:
Photocurrent is the current produced when light falls on a photodiode or a metal with suitable work function. Work function is defined as the minimum energy required to eject an electron from the surface of the material. It also corresponds to the minimum frequency, the photon of which when falls on the surface of a metal, the photoelectron gets ejected. This phenomenon of ejection of an electron is known as photoelectric effect.
A solar cell is constructed by selecting suitable material so that it’s easy to generate current. Generally the material having less work function is selected.
It is based on the principle that when solar radiation falls on the surface of metal in a solar cell, the electrons on the surface of metal get excited and hence current is generated. This current is collected by applying certain potential differences across the solar cell.

Additional Information:
The magnitude of current generated is independent of the intensity of light. This phenomenon of photoelectric effect could be explained by the particle nature of the light.

Note:
This is a very useful and non-polluting source of energy. It's only disadvantage is that it has a very high initial cost of installation. The potential difference generated by the photo electrons could be determined by using the method of stopping potential which is the minimum potential difference required to stop the most energetic photoelectron.