Question

Photovoltaic energy is the conversion of sunlight into

• A. Chemical energy
• B. Biogas
• C. Electricity
• D. Geothermal energy

Answer 1

The correct option is C

Electricity

Explanation for correct option

Photovoltaic energy

1. The conversion of sunlight into electricity is known as photovoltaic energy.
2. A photovoltaic cell, also known as a solar cell or PV, is the technology that converts solar energy into electrical power directly.
3. Photovoltaic cells are non-mechanical devices comprised primarily of silicon alloys.
4. A photovoltaic cell is a device that operates on the principle of the photovoltaic effect.
5. The potential barrier in an open-circuited non-illuminated pn junction adjusts so that the resultant current is zero.
6. When the junction is illuminated electron-hole pairs are generated on each side of the junction.
7. As the minority carriers (electrons of p-side and holes of n-side) move down the potential barrier, it causes an increase in reverse current.
8. But since the diode is in an open circuit the resultant current must be zero.
9. So the majority current must increase by the same amount as the minority current.
10. The increase in majority current is affected by the decrease in barrier height in the presence of incident light.
11. As a result, a potential difference develops across an open-circuited illuminated pn junction.
12. Actually, the pn develops due to the accumulation of excess majority carriers in their respective regions.
13. This is known as the photovoltaic effect Photovoltaic cell uses this effect to convert light energy into electrical energy.
14. When sunlight is used as an incident photon, photovoltaic cells are called solar cells.
15. A solar cell is basically a pn junction with a large surface area that can convert solar radiation, directly into electrical energy.
16. The construction of a basic solar cell consists of a shallow pn junction, a front ohmic contact either along the edge or around the perimeter, and a back ohmic contact that covers the entire back surface.
17. The top surface is designed to expose a maximum portion of it to the incident sunlight.
18. The surface is also coated with appropriate material to reduce reflection and decrease surface recombination.
19. The surface layer of a-type material is made extremely thin (~mm) such that light can penetrate the junction.

The explanation of the incorrect option

In case of option A

Photosynthesis is the process in which light energy is converted to chemical energy in the form of sugars.

In case of option B

Photovoltaic (PV) systems convert sunlight directly to electricity and not biogas.

In case of option D

PV systems convert sunlight directly to electricity rather than geothermal energy.

Hence, option C is the correct answer.