What is potential difference measured in?

• A. The energy put into circuit by the source or used by a load (in Volts)
• B. The current flowing through a circuit
• C. The energy stored in a capacitor
• D. The resistance across a component

Answer: (A)

Potential difference is about how much energy is transferred to or from a unit of electric charge as it moves between two points in a circuit. It tells you the energy supplied by the source or the energy used by a component per coulomb of charge, which is why it’s measured in volts. One volt equals one joule of energy per coulomb of charge.

The current is about how much charge flows per second, not the energy per charge. The energy stored in a capacitor refers to the total energy in the capacitor, which depends on voltage but isn’t itself the measurement of potential difference. Resistance is a property that relates voltage and current, measured in ohms.