Question

Write any five applications of photoelectric cells.

Answer 1

Hint: The photoelectric cells or photocells works on the principle of the photoelectric effect. The main principle of the photocells is to convert the light energy into electrical energy and the application of the photocells is based on this principle.

Complete step by step solution:
There are many applications of photoelectric cells in our daily lives. Given below are 5 important applications of photoelectric cells:
1. Photoelectric cells are used to control the temperatures of furnaces.
2. Photoelectric cells are used in the study of the spectra of stars and temperature.
3. Photoelectric cells are used in cinematography to reproduce sound.
4. Photoelectric cells are used in street lights so that they can be switched on and off automatically.
5. Photoelectric cells are used during space travel to obtain electrical energy from sunlight.

Additional information:
A photoelectric cell is an application of the photoelectric effect. A photoelectric cell has a semi-cylindrical photosensitive metal plate, called the emitter and a wire loop called the collector which is supported by an evacuated glass or quartz bulb. This is then connected to an external circuit with a microammeter and a high-tension battery. When light having a suitable wavelength falls on the emitter, photoelectrons will be emitted. The photoelectrons will then be drawn towards the collector photocell and will convert the change in the intensity of illumination into a change in the photocurrent. The minimum of anode potential that can stop the photocurrent is known as the stopping potential, which can stop even the most energetic electrons. This stopping potential only depends on the work function of the metal and the wavelength of light. The stopping potential has no relation to the intensity of light.

Note:
The light is incident on a metal surface the electrons are released. This phenomenon is called the Photoelectric effect and the electrons thus released are called Photo electrons. This effect is possible only if we consider the light as the particle and it will not satisfy the condition for the wave nature.