9702 · 9.2
Potential difference and power flashcards
Revision flashcards for Cambridge 9702 Potential difference and power (syllabus 9.2). Flip, recall, then mark a real past-paper question.
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What is potential difference (p.d.)?
The energy transferred or work done per unit charge as it moves between two points in a circuit.
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What is the SI unit for potential difference?
The Volt (V), defined as one Joule per Coulomb (1 J/C).
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What does electrical power measure?
The rate at which electrical energy is transferred or converted into other forms within a circuit.
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What is the SI unit for power?
The Watt (W), which is equivalent to one Joule per second (1 J/s).
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What is the fundamental formula for power in terms of energy and time?
$P = \frac{\Delta E}{\Delta t}$ (Power equals change in energy divided by change in time).
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What is the primary formula for electrical power, using potential difference and current?
$P = VI$ (Power equals potential difference multiplied by current).
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How can electrical power be calculated using potential difference (V) and resistance (R)?
$P = \frac{V^2}{R}$.
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How can electrical power be calculated using current (I) and resistance (R)?
$P = I^2R$.
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How do you calculate the total electrical energy transferred over a duration?
$E = VIt$ (Energy equals potential difference × current × time).
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What does 1 Volt signify?
It means 1 Joule of energy is transferred for every 1 Coulomb of charge that passes between the two points.