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Electric field intensity and electric potential

The electric field intensity at a point can be defined as the negative of the potential gradient at that point. i.e.

Electric field intensity = - Potential gradient      E = dV/dx

Notice the negative sign - this implies that measuring from the positive plate the potential drops with increasing distance.

In the uniform field the electric field intensity is the same anywhere in the field (hence the name) and therefore you should see that the potential decreases steadily with distance from one plate to the other. [dV = -Edx]

However in a radial field E is not constant and is then truly the gradient of the potential-distance curve at any point.

Graph of potential gradient and electric field intensity for a radial field

© Keith Gibbs 2011