Electric Potential Formulae & Examples | What is Electric Potential? – Video & Lesson Transcript | Study.com

What is Electric Potential?

Electric potential is electric potential energy or work per unit of charge. For example, a 1.5 V battery has an electric potential of 1.5 volts which means the battery is able to do work or supply electric potential energy of 1.5 joules per coulomb in the electric circuit. A power source of 550 volts means it is able to push 550 joules of energy for every coulomb of charge. So, {eq}V=\frac {W}{q} {/eq}, where V is the electric potential (V) and W is the electric potential energy (J), and q is the charge (C): Volt is joule per coulomb or V=J/C.

An electric potential can also be defined in terms of the electric field. To know what is electric potential recall that the electric field influences any charge placed in it by exerting an electric force F=q*E. But electric potential energy, or work that is needed to move the charge for a distance of r, is W=F*r.

Substituting equations give: {eq}V=\frac {W}{q}=\frac {F*r}{q}=\frac {q*E*r}{q}=E*r {/eq}.

So, the electric potential definition can be also put as the electric field multiplied by the distance r: {eq}V=E*r {/eq} where E is measured by newton per coulomb (N/C), and r measured by meters, V is measured by volts: Volt is equal to newton meter per coulomb or V={eq}\frac {N*m}{C} {/eq}.

The famous physicist Alessandro Volta studied electric circuits and discovered that voltage or electric potential difference between two points A and B in an electric circuit is defined as the difference in the number of charges between the two points A and B. Electric potential or voltage is different from the electric current in a circuit as voltage can also be defined as the means by which we measure the push of electricity. So, an electric potential is the level of power behind a flow of electricity but shouldn’t be confused with the electric current itself. Recall that charge density is the same as saying the density of charged particles which can be defined as the number of charges per unit of length, area, or volume.

For example, in a closed circuit in series that is made of a power source such as a battery and two resistors the electric current remains the same while electric potential drops across each resistor. An electric current in an electric circuit is the movement of charges while the electric potential is the difference in the charge’s density between two points in the circuit. While an electric current passes through a resistor connected at two points C and D it slows down due to its resistance to the charge’s movements. The slowing down of movement causes a difference in the charge’s density between the two points C and D and, therefore, leads to a voltage or electric potential difference across the resistor. Voltage can be compared to the water pressure in the shower.

Two resistors and a battery in Series Circuit