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Programme 19: Circuits
Activity Sheet 2
Resistance of Wire
An experiment was done to find the resistance of some wire. The
wire was connected in a circuit. As the voltage was increased the
current was measured. Here are the results for 2 different
wires:
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Wire A
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Wire B
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Voltage (V)
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Current (A)
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Voltage (V)
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Current (A)
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2
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0.3
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2
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0.1
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4
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0.6
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4
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0.2
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6
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0.9
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6
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0.3
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8
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1.2
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8
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0.4
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10
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1.5
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10
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0.5
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12
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1.8
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12
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0.6
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1. Use graph paper to plot a graph of voltage V (in volts) on
the vertical axis against current I (in amps) on the horizontal
axis. Plot the graph for wire A and wire B on the same axes.
2. Do the wires obey Ohm’s Law? How can you tell?
3. Which wire has the highest resistance?
The resistance R can be calculated from the gradient of
the graph R = V/I
4. Calculate the resistance of wire A and wire B.
(Remember to use the units of resistance for your answers.)
Here are some results for a component:
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Voltage (V)
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Current (A)
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0
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0
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2
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0.4
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4
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0.7
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6
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0.9
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8
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1.0
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10
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1.06
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12
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1.1
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5. Plot the graph of voltage against current for this
component.
6. Does this component obey Ohm’s Law?
7. Can you suggest what the component might be?
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