An equipotential line is a line joining points having the same potential.

- If an object is moved from one point on a line of equipotential to another point on the same line, there is no change in its potential. Hence, no work is done.
- Equipotential Lines are always perpendicular to electric field lines.

Distance between lines for equal increment of potential for electric field due to **point charges** is always increasing.

Distance between lines for equal increment of potential for electric field due to **parallel plate** is always the same.

A positive test charge will tend to move to a lower potential while a negative test charge will tend to move to a higher potential.

The field strength at a point is numerically equal to the potential gradient at that point.

$E = \, – \frac{dV}{dr}$

$E = \, – \frac{\Delta V}{\Delta r}$

, only applicable for parallel plates