Electric Potential and Potential Energy

Work done moving charge in a field.

The potential at a point is the work needed per unit charge to bring a positive test charge there from far away. Around a point charge it falls off as one over the distance. Surfaces of equal potential are perpendicular to the field lines, and no work is done moving along them.

In a uniform field, the field strength equals the potential difference divided by the separation. The electron-volt is the energy gained by an electron through one volt and is a handy unit in electronics and atomic physics.

• Potential is a scalar; field is a vector.
• 1 eV = 1.6 × 10⁻¹⁹ joule.
• Field points from high to low potential.

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