Opposite Charges Attract - Electric Fields, Electrostatics & Capacitors Step by Step

A positive charge and a negative charge pull toward each other. The force pair is still equal in size and opposite in direction.

electrostatics Opposite charge signs make the force pair point toward the space between the charges.

Example

A positive charge and a negative charge pull toward each other. The force pair is still equal in size and opposite in direction. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

The signs are opposite

Put a positive 2 coulomb charge on the left and a negative 3 coulomb charge on the right.

q_{\text{left}} = +2\ \text{C}\qquad q_{\text{right}} = -3\ \text{C}

Opposite signs attract

Because the signs are opposite, each charge is pulled toward the other one. The left force points right, and the right force points left.

+ \text{ with } - \Rightarrow \text{attract}

The pair is still equal and opposite

Attraction changes the directions, not the pair rule. Each charge feels a force of 6 newtons, and the arrows point toward each other.

F_{\text{left}} = F_{\text{right}} = 6\ \text{N}

Attraction still uses matched sizes

The sign change flips the arrow directions, not the equality of the pair. The diagram draws the 6 newton row; the table shows that the size match is the rule.

\begin{array}{c|c}F_{\text{left}}&F_{\text{right}}\\4\ \text{N}&4\ \text{N}\\6\ \text{N}&6\ \text{N}\\8\ \text{N}&8\ \text{N}\\\end{array}