Potential Difference
Potential Difference
- Current describes charge flow. Potential difference describes energy transferred for each coulomb.
- Potential difference is measured between two points, so a voltmeter is connected across a component.
Energy transferred per charge
Definition
2 marksWhat is meant by potential difference across a component?
Model answer: The energy transferred to the component per unit charge passing through it.
Symbols
- = potential difference (V)
- = energy transferred (J)
- = charge passing (C)
- . A 6.0 V lamp transfers 6.0 J from every coulomb passing through it.
- A larger p.d. means more energy transferred per coulomb. It does not by itself tell us the current or the power.
Translate words, units and numbers
Worked example
Energy transferred in a component
A charge of 15 C passes through a motor with a p.d. of 12 V. Calculate the energy transferred.
- Rearrange to .
- .
Answer
Your turn9702/22/M/J/25 Q6(a)
Define the potential difference across a component. [2] (9702/22/M/J/25 Q6(a))
Show worked answer
It is the energy transferred to the component per unit charge passing through it.