Define potential difference .

The energy transferred per unit charge flowing from one point to another.

How should a voltmeter be connected to measure the potential difference across a component?

In parallel with the component.

True or False? The potential difference of a power supply connected in series is the same across every component in the circuit.

False. The potential difference is shared between the components in a series circuit.

One volt is equivalent to one .......... per coulomb.

One volt is equivalent to one joule per coulomb.

A lamp on a 240 V supply and a lamp on a 12 V supply carry the same current, yet the 240 V lamp glows more brightly. Explain why, in terms of energy transfer.

The 240 V lamp has a potential difference 20 times greater than the 12 V lamp. Since potential difference is the energy transferred per unit charge , each coulomb of charge transfers 20 times more energy to the 240 V lamp, making it shine more brightly.

Define electrical power .

The rate of doing work (rate of energy transfer) by an electrical device.

True or False? For a fixed resistance, doubling the current doubles the power dissipated.

False. Power is proportional to current squared , so doubling the current makes the power four times greater .

A LevelPhysicsCambridge (CIE)Flashcards9. ElectricityPotential Difference & Power

Potential Difference & Power (Cambridge (CIE) A Level Physics): Flashcards

Exam code: 9702

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Define potential difference.

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Cards in this collection (12)

Define potential difference.
The energy transferred per unit charge flowing from one point to another.
How should a voltmeter be connected to measure the potential difference across a component?
In parallel with the component.
True or False?
The potential difference of a power supply connected in series is the same across every component in the circuit.
False.
The potential difference is shared between the components in a series circuit.
One volt is equivalent to one .......... per coulomb.
One volt is equivalent to one joule per coulomb.
State the equation relating potential difference, work done and charge.
$V = \frac{W}{Q}$
A lamp on a 240 V supply and a lamp on a 12 V supply carry the same current, yet the 240 V lamp glows more brightly. Explain why, in terms of energy transfer.
The 240 V lamp has a potential difference 20 times greater than the 12 V lamp. Since potential difference is the energy transferred per unit charge, each coulomb of charge transfers 20 times more energy to the 240 V lamp, making it shine more brightly.
Define electrical power.
The rate of doing work (rate of energy transfer) by an electrical device.
State the equation relating power, current and potential difference.
$P = I V$
State the equation for power in terms of current and resistance only.
$P = I^{2} R$
State the equation for power in terms of potential difference and resistance only.
$P = \frac{V^{2}}{R}$
True or False?
For a fixed resistance, doubling the current doubles the power dissipated.
False.
Power is proportional to current squared, so doubling the current makes the power four times greater.
$P = I^{2} R$ shows that, for a fixed resistance, power dissipated is proportional to the current ...........
$P = I^{2} R$ shows that, for a fixed resistance, power dissipated is proportional to the current squared.

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