Question

A polythene piece rubbed with wool is found to have a negative charge of $6 \times {10^{ - 7}}$ C. What is the number of electrons transferred to polythene from wool?
$
  {\text{A}}{\text{. }}3.75 \times {10^{10}} \\
  {\text{B}}{\text{. 9}}{\text{.6}} \times {10^{10}} \\
  {\text{C}}{\text{. 9}}{\text{.6}} \times {10^{12}} \\
  {\text{D}}{\text{. }}3.75 \times {10^{12}} \\
 $

Answer 1

Hint: Here, we will proceed by explaining the concept of quantization of charge. Then, we will be using the formula corresponding to this concept from which we will get the number of electrons transferred.
Formula Used: Q = ne

Complete Step-by-Step solution:
Given, Charge Q = $6 \times {10^{ - 7}}$ C
Electric charge is the electrons transfer from one material to another. So negative charging means there's an excess of electrons, while positive charging is an electron deficiency.
According to electric charge conservation, the electric charge can neither be created nor destroyed, but it can only be transferred from one part of the system to another part so that the total charge of an isolated system remains constant.
Charging quantization means that when we say that something has a given charge, we mean that is how many times the charge of a single electron it has. This is true, since all charges are connected with an entire electron.
Q = ne where Q denotes the charge, n denotes the number of electrons transferred and e denotes the charge on one electron (i.e., e = $1.6 \times {10^{ - 19}}$ C)
By substituting Q = $6 \times {10^{ - 7}}$ C and e = $1.6 \times {10^{ - 19}}$ C in the equation Q = ne, we get
$
   \Rightarrow 6 \times {10^{ - 7}} = n\left( {1.6 \times {{10}^{ - 19}}} \right) \\
   \Rightarrow n = \dfrac{{6 \times {{10}^{ - 7}}}}{{1.6 \times {{10}^{ - 19}}}} \\
   \Rightarrow n = \dfrac{6}{{1.6}} \times {10^{ - 7 + 19}} \\
   \Rightarrow n = 3.75 \times {10^{12}} \\
 $
Therefore, the number of electrons transferred to polythene from wool is $3.75 \times {10^{12}}$ electrons.
Hence, option D is correct.

Note- Quantization of charge is only important at the microscopic level because moving electrons as a term is obsolete as we pass to the macroscopic level because charges there are assumed to be constant. If an object has a positive or negative charge depends on (or from) the number of electrons that it is transferred to.