Which quantity is defined as the energy per unit charge supplied by a source to move charges around a circuit?

Which quantity is defined as the energy per unit charge supplied by a source to move charges around a circuit?

• A. Electromotive force
• B. Potential difference
• C. Current
• D. Electric field

Answer: (A)

Energy per unit charge supplied by a source to move charges around a circuit is electromotive force. This describes how much energy the source gives to each coulomb of charge as it powers the loop, and it is measured in volts. Potential difference, in contrast, is the energy per unit charge moved between two points in the circuit, such as across a component; it reflects energy changes along the path rather than what the source provides to drive the current. Current is the rate at which charge flows, not energy per unit charge, and the electric field is the force per unit charge acting on charges, not the energy supplied by the source. Because the definition centers on the energy the source delivers to move charges around the circuit, the term that fits is electromotive force.

Energy per unit charge supplied by a source to move charges around a circuit is electromotive force. This describes how much energy the source gives to each coulomb of charge as it powers the loop, and it is measured in volts. Potential difference, in contrast, is the energy per unit charge moved between two points in the circuit, such as across a component; it reflects energy changes along the path rather than what the source provides to drive the current. Current is the rate at which charge flows, not energy per unit charge, and the electric field is the force per unit charge acting on charges, not the energy supplied by the source. Because the definition centers on the energy the source delivers to move charges around the circuit, the term that fits is electromotive force.