That the current through a resistor at constant temperature is directly proportional to the potential difference across the resistor.

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What does reversing the current through a component do?

Reverses the potential difference across it.

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How is the current through a component measured?

With an ammeter.

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How are ammeters always placed and what is the unit of current?

Ammeters are always placed in series with the component and the unit of current is the ampere/amp (A).

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How is the potential difference (pd) across a component measured?

With a voltmeter.

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How are voltmeters always placed and what is the unit of potential difference (pd)?

Voltmeters are always placed in parallel with the component and the unit of potential difference is the volt (V).

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What equation is used to calculate potential difference (pd), work done and charge?

V = W over Q (look up).

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In the equation used to calculate potential difference (pd), work done and charge, what is V?

The potential difference (pd) in volts (V).

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In the equation used to calculate potential difference (pd), work done and charge, what is W?

The work done in joules (J).

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In the equation used to calculate potential difference (pd), work done and charge, what is Q?

The charge in coulombs (C).

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In the equation used to calculate potential difference (pd), work done and charge, V = W over Q, what part of this equation can be replaced by E and how?

W because work done is equal to energy transferred in joules (J).

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What is resistance?

The opposition to current flow.

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What is the unit of resistance?

ohm (look up the symbol for this - it looks like a strange upside down horseshoe).

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What equation is used to calculate the resistance of a component?

R = V over a slanted I (look up because it is not clear).

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In the equation used to calculate the resistance of a component, what is R?

Resistance in ohms (the weird horseshoe looking symbol).

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In the equation used to calculate the resistance of a component, what is V?

The potential difference in volts (V).

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In the equation used to calculate the resistance of a component, what is slanted I (again check this online)?

The current in amps (A).

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Wha are current-potential difference graphs used for?

To show how the current through a component varies with the potential difference across it.

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How is Ohm's law shown on a graph?

If a resistor is kept at a constant temperature, the current-potential difference graph shows a straight line passing through the origin. This means the current is directly proportional to the potential difference (pd) across the resistor.

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What is any component that follows Ohm's law called?

An ohmic conductor.

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What device is used to measure current?

An ammeter.

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What is the unit of resistance?

Ohm (weird horseshoe symbol).

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What are ammeters always connected in?

Series.

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What are voltmeters always connected in?

Parallel.

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**LOOK UP A CURRENT-POTENTIAL DIFFERENCE GRAPH FOR A RESISTOR**

**

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Other cards in this set

Card 2

Front

What does reversing the current through a component do?

Back

Reverses the potential difference across it.

Card 3

Front

How is the current through a component measured?

Back

Card 4

Front

How are ammeters always placed and what is the unit of current?

Back

Card 5

Front

How is the potential difference (pd) across a component measured?

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