Hello,

Charge quantization is the principle that the charge of any body is in integral multiple of elementary charge. An elementary charge is the electrical charge carried by a single electron . that simply implies that charge cannot be taken as2.5 or 6.9 like that whenever we will talk about charge we will have to take the full charge of a single electron. Milikan's oil drop experiment has described this quantization of charge.

Hope you understand .

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