Question

Write the CGS and SI unit of charge. Give the relation between them.

Answer 1

Hint: In this question, we have been asked to write the SI and CGS unit of charge. We have also been asked to state the relation between the SI unit and CGS unit of charge. Therefore, to answer this question, we shall first briefly discuss the SI and CGS unit system. Later, we shall try to write the unit of charge. By discussing the SI and CGS unit system, we shall also be able to provide a relation between the SI unit of charge and CGS unit of charge.

Complete step by step answer:
The centimetre gram second system (CGS) system is a variation in metric system based on centimetre as the unit of length, gram as the unit of mass and second as a unit of time. On the other hand, International system of units or (SI) system is a metric system with metre as unit of length, kilogram as the unit of mass and second as a unit of time. The SI unit system is widely accepted everywhere. Every complex unit can be derived from the basic unit such as length, time or mass.
The electric charge is a property of matter. It causes the body to experience force when it is placed in an electromagnetic field. The similar charges i.e. two positive or two negative charges when brought in proximity will repel each other.
The SI unit of charge is Coulomb and the CGS unit of charge is esu.
The CGS unit of charge is also known as statcoulomb.
The relation between Coulomb and Statcoulomb is given by,
$$1C=3\times {10}^{9}esu$$

Note:
If two stationary objects carry a charge of 1 esu each, they will electrically repel each other with a force of 1 dyne. The repulsive force between the objects can be given by Coulomb’s law. The CGS system was proposed by German mathematician Carl Friedrich Gauss. Since 1940, after the acceptance of the SI unit system, the use of the CGS system has been reduced all over the world.