Potential gradient is numerically equal to electric field strength E . Potential gradient is potential difference divide by distance (V/d) .
If E is constant, potential vs distance graph will be a straight line with constant gradient(E)
If E is not constant , potential vs distance graph will be a curve . Increasing gradient means greater E and vice versa. Equipotential lines are closer and closer together if drawn. If equipotential lines are further and further apart , then the
E is decreasing.
The direction of E however is in the direction of decreasing potential. The E vector is perpendicular to the equipotential lines.
