Chapter 21.1, Problem 19SSC

To determine

The way in which the electric field acting on a test charge differ from the force on that charge.

Explanation of Solution

Introduction:

The electric field strength on a charge $q\text{'}$ is given by,

  $E=\frac{F_{\text{on }q\text{'}}}{q\text{'}}$

Where,

  $F_{\text{on }q\text{'}}=\text{Electric force on }q\text{'}$

As can be seen from above formula, the electric field strength acting on a test charge results in the electrostatic force acting on it which is given as,

  $F_{\text{on }q\text{'}}=q\text{'}E$

Thus, if any charged particle is kept in external electric field, then force will act on it due to this external electric field.

Conclusion:

Hence, the force acting on a charge depends on the electric field acting on it.