Electric Potential

Source: Yong P. Chen, PhD, Department of Physics & Astronomy, College of Science, Purdue University, West Lafayette, IN Electric potential, also known as "voltage", measures the electric potential energy per unit charge. Electric field is a scalar quantity and is fundamental to many electrical effects. Like potential energy, what is physically meaningful is the difference in the electric potential. For example, the spatial variation in the electric potential is related to the electric...

Suppose a positive test charge moves away from a positive static charge, then the Coulomb force does positive work, and its electric potential energy decreases. The potential energy per unit charge is defined as the electric potential. The electric potential is independent of the test charge. When a test charge moves from the initial to the final position, the electric potential difference between those positions is defined as the ratio of the change in the potential energy to the charge on the...

For a system of charges, it is easy to calculate the system's potential because potential is a scalar quantity. However, in some instances where calculating the electric field is more straightforward than finding the potential, the electric field is used to calculate the system's potential. For a positive charge, the electric field is radially outward, and the potential is positive at any finite distance from the positive charge. In such an electric field, the motion away from the positive...

Consider a ring of radius R with a uniform charge density λ. What will the electric potential be at point M, which is located on the axis of the ring at a distance x from the center of the ring? The ring is divided into infinitesimal small arcs such that point M is equidistant from all the arcs. Here, the cylindrical coordinate system is used to calculate the electric potential at point M. A general element of the arc between angles θ and θ + dθ is of the length Rdθ and has a charge of λRdθ.

An electric dipole is a system of two equal but opposite charges, separated by a fixed distance. This system is used to model many real-world systems, including atomic and molecular interactions. One of these systems is the water molecule, but only under certain circumstances. These circumstances are met inside a microwave oven, where electric fields with alternating directions make the water molecules change orientation. This vibration is equivalent to heat at the molecular level. Consider a...