Chapter 27, Problem 78A

To determine

To Find: The magnitude of second charge.

Answer to Problem 78A

  $5.0\times {10}^{-7}\text{C}$

Explanation of Solution

Given data:

Magnitude of first charge, $q_1=8.0\times {10}^{-7}\text{C}$

Coulomb force between two charges, $F=\text{9}\text{.0}\text{N}$

Distance between the charges, $r=\text{ 0}\text{.02 m}$

Formula used:

As per Coulomb’s law:

  $F=k\frac{q_1{q}_2}{r^2}$

Here, k is the Coulomb constant.

Calculation:

Substitute the values and solve:

  $F=k\frac{q_1{q}_2}{r^2}$

  $\begin{array}{l}9.0=\frac{9\times {10}^9\times 8.0\times {10}^{-7}\times q_2}{{0.02}^2}\\ q_2=5.0\times {10}^{-7}\text{C}\end{array}$

Conclusion:

Thus, the magnitude of second charge is $5.0\times {10}^{-7}\text{C}$ .