The energy per electron is very small in macroscopic situations like that in the previous example—a... Conservation of Energy. To describe the electric field we introduce the idea of electric potential difference. Potential difference formula. When a Coulomb of charge (or any given amount of charge) possesses a relatively large quantity of potential energy at a given location, then that location is said to be a location of high electric potential. If the charge is uniform at all points, however high the electric potential is, there will not be any electric field. Units of potential difference are joules per coulomb, given the name volt (V) after Alessandro Volta. Electric potential is a location-dependent quantity that expresses the amount of potential energy per unit of charge at a specified location. In the previous section of Lesson 1, the concept of electric potential was introduced. ΔV=V B-VA=W AB /q 0 =ΔU/q 0 The potential difference between two points A and B in an electric field is defined as “The work is done in carrying a unit positive charge from points A to B while keeping the charge in equilibrium. The work done per unit charge in moving a charge between two points in an electric field is known as the electric potential difference, (V). Thus, the relation between electric field and electric potential can be generally expressed as – “Electric field is the negative space derivative of electric potential.”. [latex]1\text{V}=1\frac{\text{J}}{\text{C}}\\[/latex] Electric Potential Difference The electric potential difference between points A and B, VB − VA, is defined to be the change in potential energy of a charge q moved from A to B, divided by the charge. The expression for the magnitude of the electric field between two uniform metal plates is. Thus, the above formula is sayingthat the -component of the electric field at a given point in space is equalto minusthe local gradient of the electric potential in the-direction. E = V AB d E = V AB d. Since the electron is a single charge and is given 25.0 keV of energy, the potential difference must be 25.0 kV. The units of electric potential are volts, where a volt is equal to 1 Joule per Coulomb. 7.3: Electric Potential and Potential Difference The Electron-Volt. The electric field exists if and only if there is a electric potential difference. And similarl… Entering this value for VAB and the plate separation of 0.0400 m, we obtain. 1V = 1J/C The potential difference between points A and B, V B − V A, is thus defined to be the change in potential energy of a charge q moved from A to B, divided by the charge. It basically measures how fastthe potential varies as the coordinate is changed (but thecoordinates and are held constant). Units of potential difference are joules per coulomb, given the name volt (V) after Alessandro Volta.