Question

How many electronic charges form 1 coulomb?
$$\begin{gathered} A.9.1\times {10}^{-31} \\ B.1.6\times {10}^{18} \\ C.62.5\times {10}^{17} \\ D.1.76\times {10}^{11} \end{gathered}$$

Answer 1

Hint- In order to find the number of electronic charges we will use the charge of electron which is given as $e=1.6\times {10}^{-19}C$ and we will proceed further by using the formula relating the total charge and the number of charged particles.

Formula used- $q=ne$

Complete step-by-step answer:

We know the charge is negative on an electron, so it is negative $e=1.6\times {10}^{-19}C$
We need to quantify the number of electrons which constitute one charging coulomb.
Total charge required 1 Coulomb.
Therefore $q=1C$
We know the formula relating total charge and the number of charged particle is given as:
$$\begin{gathered} q=ne \\ \Rightarrow n={\displaystyle \frac{q}{e}}.........(1) \end{gathered}$$
Where q is the net charge, n is the number of charged particles and e is the charge of each particle.
Substituting the values in equation (1) we get:
$$\begin{gathered} \because n={\displaystyle \frac{q}{e}} \\ \Rightarrow n={\displaystyle \frac{1C}{1.6\times {10}^{-19}C}} \\ \Rightarrow n={\displaystyle \frac{1\times {10}^{19}}{1.6}} \\ \Rightarrow n={\displaystyle \frac{100\times {10}^{17}}{1.6}} \\ \Rightarrow n=62.5\times {10}^{17} \end{gathered}$$
Hence, $$62.5\times {10}^{17}$$ electronic charges form 1 coulomb.
So, the correct answer is option C.

Note- One coulomb is equal to the amount of charge from a current of one ampere flowing for one second. One coulomb is equal to the charge on $$62.5\times {10}^{17}$$ electrons. The charge on 1 electron is $e=1.6\times {10}^{-19}C$ of negative charge. Students must remember the value of charge present on one electron to solve such problems. Also $e=1.6\times {10}^{-19}C$ of positive charge is present on one proton.