Question

Additive nature of charge can be explained by
A. Law of conservation of electric charge
B. Law of quantisation of electric charge
C. Law of superposition of electric charge
D. None of the above

Answer 1

Hint: When a body or object has deficiency or excess of electrons then the body is said to be charged. When a body has excess electrons then the body is negatively charged or the body has a shortage of electrons then the body is said to be positively charged.

Complete answer:
Properties of electric charge:

(i)Charge is a scalar quantity because charge does not have a direction. The charge is capable of travelling in a particular direction which is due to the potential difference between the two places but there is no characteristic direction to charge itself.

(ii)Discrete nature or quantisation of charge: First it was assumed that the charge on a body is continuous in nature. But later on the basis of atomic theory it was proved that the charge carried by a body is not continuous but discrete. Charge on a body is an integral multiple of the smallest unit of charge I.e electronic charge. Thus charge is said to have discrete nature and said to be quantised.
Mathematically,
$Q=ne$
Where
$\begin{align}
  & n=\pm 1,\pm 2,\pm 3... \\
 & e=1.6\times {{10}^{-19}} \\
\end{align}$
n is positive for positive charge and negative for negative charge.

(iii)Law of conservation of charge: The law of conservation of charge states that the total charge in an isolated system remains constant.

(iv)Additive nature of law of superposition of charges: The total charge on a body is equal to the algebraic sum of all charges located at different points or in different regions of the body.

(v)Invariance of charge: the total amount of charge remains constant when converted from one inertial frame of reference to another frame of reference.
So the only property describing the additive nature of charge is the principle of superposition of charges.

So, the correct answer is “Option C”.

Note:
Note that charge is capable of being transferred from one body to another body if they are connected to each other through a conductor. During charge transfer the following conditions hold good.

(i)Transfer of charges takes place due to transfer of free-electrons.
(ii)Direction of flow depends upon the electric potential difference between the bodies.
(iii) Electrons tend to move from low potential to high potential.
(iv) Algebraic sum of charges remains constant.