What is meant by ‘Quantization of Charge’?

Quantization of charge is a fundamental concept in physics that refers to the observation that electric charge comes in discrete, indivisible units. In other words, all electric charges in the universe are multiples of a fundamental unit of charge, denoted by "e."

The elementary charge (e) is the charge of a single proton or electron. It has a magnitude of approximately 1.602 x 10^-19 coulombs (C). Since protons have a positive charge and electrons have a negative charge, the magnitude of their charges is equal, but they differ in sign. The quantization of charge means that any charged object will have a total charge that is an integer multiple of the elementary charge (±e).

Mathematically, the quantization of charge can be expressed as:

q = n * e

where:

q is the total charge of an object,
n is an integer (positive, negative, or zero), and
e is the elementary charge.
This discovery was a significant development in understanding the nature of electric charge and is an essential principle in modern physics, particularly in the field of quantum mechanics and particle physics. The concept of quantization of charge was first experimentally observed by Robert Millikan in his famous oil drop experiment, where he measured the charge on individual oil droplets and found that the charges were always multiples of the elementary charge.