Voltage is commonly used as a short name for electrical potential difference. Its corresponding SI unit is the volt (symbol: V, not italicized). Electric potential is a hypothetically measurable physical dimension, and is denoted by the algebraic variable V .The voltage between two (electron) positions 'A' and 'B', inside a solid electrical conductor (or inside two electrically-connected, solid electrical conductors), is denoted by (VA − VB). This voltage is the electrical driving force that drives a conventional electric current in the direction A to B. Voltage can be directly measured by an 'ideal voltmeter'. Well-constructed, correctly used, real voltmeters approximate very well to ideal voltmeters.
For a conductor, any excess charge must reside on the surface.
Second, the electric field inside the conductor is zero. Third, E on the surface is perpendicular to the surface,
and is given by sigma/epsilon_0, where sigma is the surface charge density. Fourth, the whole conductor is an
equipotential region; i.e., all points on or within the conductor are at the same potential.
If a conducting sphere has a total charge Q distributed on its
surface, the potential inside the sphere is given by kQ/R, where R is the radius of the sphere.
In a cavity within a conductor, the electric field is zero; if it
were not, the inner surface of the conductor would not be an equipotential surface. The vanishing of E in the
cavity explains why conductors are used as electrical shields.
Electric Potential, Part 4
Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.