Potential difference
The energy transferred per unit of charge as it moves between two points, measured in volts (V). It is what pushes the current round.
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Analogy
The push from a pump: a bigger pump pushes water harder.
Example
V = 6 V, charge = 4 Cenergy = V x chargeenergy = 6 x 4 = 24 J
In practice
A 1.5 V cell gives each coulomb of charge 1.5 J of energy. Voltage is measured with a voltmeter placed in parallel.
Practice
Flashcards
- How is a voltmeter connected?In parallel with the component.
Questions people ask
What does a voltmeter measure?
A voltmeter measures the potential difference across a component, which is how much energy each coulomb of charge gives to it. It is connected in parallel with the component, on separate branches that join either side of it, so only a tiny amount of current flows through the meter.
What is the difference between voltage and current?
Voltage is the push that makes charge move, and current is how much charge actually flows each second. A battery supplies the voltage. The current that results depends on the resistance of the circuit. High voltage with high resistance can still give only a small current.