Electric Potential

• Electric potential may be defined several ways:
  • the negative of the integral of electric field dotted with displacement
  • the scalar field of which the electric field is the negative derivative
  • the electric potential energy per unit charge at a particular point in space
  • some quantity one measures in a circuit with a voltmeter
• the units of electric potential are volts = (newton-meter/coulomb)
• in a uniform electric field, the difference in electric potential between two points is the electric field strength dotted with the displacement between the points
• real or imaginary surfaces which are at the same electric potential are called equipotential surfaces. These surfaces (or lines) are always perpendicular to the electric field
• the electric potential energy between points A and B, for a charge q, is U = q * [ V(B) - V(A) ]. Hence, another unit for electric potential is Joules per Coulomb
• we usually define electric potential to be zero at an infinite distance ... but one can pick any zero point which makes a particular problem easy to solve
• one can draw a close analogy

         electric potential : electric field  =  elevation : ground slope
  

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Copyright © Michael Richmond. This work is licensed under a Creative Commons License.