In the International System of Units (SI), electric potential is expressed in units of joules per coulomb (i.e.,volts), and differences in potential energy are measured with a voltmeter

the unit of electric potential is volts

Electric potential, the amount ofworkneeded to move a unit charge from a reference point to a specific point against anelectric field. Typically, the reference point isEarth, although any point beyond the influence of theelectric field charge can be used.



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electromagnetism: Electric fields and forces

The electric potential is another useful field. It provides an alternative to the electric field in electrostatics…

forces acting on a positivechargeqlocated between two plates, A and B, of an electric fieldE. Theelectric forceFexerted by the field on the positive charge isF=qE;to move the charge from plate A to plate B, an equal and opposite force (F′ = −qE) must then be applied. The workWdone in moving the positive charge through a distancedisW=F′d= −qEd.

Thepotential energyfor a positive charge increases when it moves against an electric field and decreases when it moves with the electric field; the opposite is true for a negative charge. Unless the unit charge crosses a changingmagnetic field, its potential at any given point does not depend on the path taken.

Although the concept of electric potential is useful in understandingelectricalphenomena, only differences in potential energy are measurable. If an electric field is defined as the force per unit charge, then byanalogyan electric potential can be thought of as the potential energy per unit charge. Therefore, the work done in moving a unit charge from one point to another (e.g., within anelectric circuit) is equal to the difference in potential energies at each point. In theInternational System of Units(SI), electric potential is expressed in units ofjoulespercoulomb(i.e.,volts), and differences in potential energy are measured with avoltmeter.

The unit of electrical potential is volt