Question

Describe the construction of a photoelectric cell.

Answer 1

A photoelectric cell which is also known as the electric Eye, Photocell, or Phototube, is an electron tube with a photosensitive cathode that is emitting electrons when it is illuminated and an anode for collecting the emitted electrons. The metals with low ionisation enthalpies are generally used in photoelectric cells. Caesium is a common example for this.

Complete step by step answer:
First of all let us take a look at what actually a photoelectric cell means. Photoelectric cell or in short photocell is an instrument that develops electricity when light shines on it. It is actually to be an electron tube with a photosensitive cathode, but nearly all modern photocells are made with two electrodes which are separated by light-sensitive semiconductor material.

Photoelectric cells are highly evacuated or the gas filled glass tube, which is an emitter and a collector. The light which is entering through a quartz window and that is falling on the semi cylindrical cathode C which is embedded with photosensitive metal. The anode is actually a straight wire of platinum or nickel which is coaxial with cathode. If the cell is needed to respond to the visible part of the spectrum, the cathode has been coated with elements like potassium or rubidium and the quartz windows are replaced by the glass.

Note:
Photoelectric cells are there in three basic types. It is based on the three different forms or modes of the photoelectric effect that they are performing. They are the photoconductive cell, the photo emissive cell, and the photovoltaic cell. Photoelectric cells are used to detect the presence of light electronically in cameras and in night vision apparatus and to produce electrical power in solar cells.