Question

What is the amount of charge on an electron?
$\begin{aligned} & \text{A}\text{. 1}\text{.6}\times \text{1}{{\text{0}}^{19}}\text{coulomb} \\\ & \text{B}\text{. 1}\text{.6}\times \text{1}{{\text{0}}^{-10}}\text{coulomb} \\\ & \text{C}\text{. 1}\text{.6}\times \text{1}{{\text{0}}^{10}}\text{coulomb} \\\ & \text{D}\text{.1}\text{.6}\times \text{1}{{\text{0}}^{-19}}\text{coulomb} \\\ \end{aligned}$

Answer 1

Hint: Charge is the basic property associated with the elementary particles. Charge on an electron and proton is of same strength but of different nature (as proton is positively charged and electron is negatively charged).

Complete step by step answer:
Matter is made up of hundreds of elementary particles among them 3 most common elementary particles are - electron, proton and neutron.
A mass is a property possessed by a body which is responsible for gravitational force like that charge is property possessed by a body that is responsible for electric force.
So, now the amount of charge on the electron is $1.6\times {{10}^{-19}}$coulomb, thus option D is correct, which is a minimum charge possible.
But how they measured the charge on an electron is the question that comes to our mind.
J.J. Thomson discovered the electron and measured the charge to mass ratio of it in 1897 but Robert Millikan measured the charge on the electron distinctly in 1909 through his “oil-drop experiment”. And, through this experiment he also verified that electric charge is discrete that it is not continuous and is always integral multiple of minimum charge or electron charge ($1.6\times {{10}^{-19}}$). We call this as quantisation of charge.
If ‘q’ is the charge on a body, then,
$q=\pm ne$
Where, n is the no. of electrons or protons(integer)
e is the minimum charge= $1.6\times {{10}^{-19}}$C
Additional information:
SI unit of charge is coulomb(C).
Dimensional formula is: [AT]
No. of electrons in 1C of charge is:
$q=\pm ne$
$\therefore n=\dfrac{q}{e}=\dfrac{1}{1.602\times {{10}^{-19}}}=6.24\times {{10}^{18}}$electrons.
Like charges repel each other unlike charges attract each other.

Note: Students may get confused with sign in power and select option A, but it is incorrect. In the correct option power of 10 has ‘- ‘sign not ‘+’sign. While answering these types of questions always cross check signs and power.