Question

State the charge on an electron in Coulomb?

Answer 1

Hint : An electron is a subatomic particle commonly represented as ${e^ - }$ or $e$. it possess negative polarity, an electron inherits the properties like- charge, mass, spin etc. the values of the electron imply the value of the charge of an electron.

Complete Step By Step Answer:
The charge on the electron is a fundamental property of a physical particle; it is the smallest unit of electric charge found free in nature.
The charge on the electron is equivalent to the magnitude of the elementary charge $(e)$ but bearing a negative sign. Since the value of the elementary charge is $1.6022 \times {10^{ - 19}}$ Coulombs, then the charge of the electron is $- 1.6022 \times {10^{ - 19}}$ Coulombs.
Oil-drop experiment
A famous method for measuring $e$ is Millikan’s oil-drop experiments. A small drop of oil in an electric field would move at a rate that balanced the forces of gravity, viscosity and electric force. The force on any electric charge in an electric field is equal to the product of the charge and the electric field. If we know the magnitude of the electric field and the weight of each particle, we can calculate the force of the electric field on a single particle and finally derive the charge.
Millikan was able to measure both the amount of electric force and magnitude of electric field on the tiny charge of an isolated oil droplet and from the data determine the magnitude of the charge itself.

Note :
When expressed in atomic units, the elementary charge takes the value of unity; i.e. $e = 1$, thus the electron’s charge can be denoted by ${e^ - }$. Although the proton is much more massive than the electrons, it only has a charge of $e$. Hence, neutral atoms always bear the same number of protons and electrons.