Question

(a) Explain the meaning of the statement ‘electric charge of a body is quantised’.
(b) Why can one ignore quantisation of electric charge when dealing with macroscopic i.e., large scale charges?

Answer 1

(a) Electric charge of a body is quantized. This means that only integral (1, 2… n) number of electrons can be transferred from one body to the other. Charges are not transferred in fraction. Hence, a body possesses total charge only in integral multiples of electric charge.

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(b) In macroscopic or large scale charges, the charges used are huge as compared to the magnitude of electric charge. Hence, quantization of electric charge is of no use on macroscopic scale. Therefore, it is ignored and it is considered that electric charge is continuous.

Answer 2

(a) The statement "electric charge of a body is quantized" signifies that the charge of any object can only be an integer multiple of the elementary charge carried by electrons or protons. A body can't possess a charge that is a fraction of this elementary charge (like \(\frac{1}{2} e, \frac{3}{2} e\), etc.).

(b) At the macroscopic level, the total number of charges present in an object is extremely large compared to the magnitude of the elementary charge. Therefore, at this scale, we treat the distribution of charge within the object as continuous. This is why the concept of quantization of electric charge can be disregarded when dealing with macroscopic objects.