Chapter 16, Problem 2P

To determine

The number of electrons that makes a charge of $-30\text{μC}$ .

Answer to Problem 2P

The number of electrons is $1.87\times {10}^{14}$ .

Explanation of Solution

Given information:

Total charge, $Q=-30\text{μC}=-30\times {10}^{-6}\text{C}$

Charge of an electron, $e=1.6\times {\text{10}}^{-19}\text{C}$

Formula used:

Write the expression to calculate the number of electrons.

  $\text{Number}\text{of electrons}=\frac{\text{Total}\text{charge}}{\text{Charge of an electron}}$ ........... (1)

Calculation:

Substitute the values in equation (1).

  $\begin{array}{c}\text{Number}\text{of electrons}=\frac{-\text{30}\times {\text{10}}^{-6}\text{C}}{-1.6\times {10}^{-19}\text{C}}\\ =1.87\times {10}^{14}\end{array}$

Here, the charge on electron is negative. So, the negative value of electron $\left(e\right)$ has been take.

Therefore, thenumber of electrons is $1.87\times {10}^{14}$ .