Question

Why can one ignore quantization of electric charge when dealing with macroscopic, i.e., large scale charges?

Answer 1

Hint: By quantization of charge, we mean that the charges are now a multiple of whole numbers considering each of these whole numbers has a charge equal in magnitude to the charge possessed by an electron. And since, the charge on a single electron is given by $1.6\times {{10}^{-19}}C$(say N), it means the charge, be it small or large, on any particle should be a multiple of N.

Complete answer:
When we talk about a charge, there is at first the parameter that decides whether the charge is positive or negative, this parameter decides the nature of the charge. The other parameter is the size or magnitude of a charge. Both the parameters are independent of each other.
Now, when we talk about macroscopic charges, we mean charges of very high order. Now these charges may range from a few Coulombs to a very high magnitude of charge. The term, very high order is, with respect to the charge of an electron which is of the order of ${{10}^{-19}}$ .
This means that macroscopic charges are very huge as compared to the magnitude of an electric charge. Therefore, quantization has no significant meaning at such a large scale. This is the reason when we are dealing with charges at macroscopic level, the quantization of charge is ignored and it is considered that the electric charge is continuous.

Note:
When we talk about quantization of a charge, it is applicable for both types of charges. One very important use of this fact can be, if we are solving a problem and the charge of a particle comes out to be less than $1.6\times {{10}^{-19}}C$, it means there is some error in our solution. We can use this simple trick to verify our answers.