Resistance of a Wire

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Resistance of a Wire

Aim

Which factors affect the resistance of a wire?

Prediction

I believe the factors which affect the resistance of a wire are:

1. The length- the increase in length could increase the resistance.

2. The thickness of the core.

3. The material of which the wire is made up of- e.g. Copper,

constantan and nichrone.

4. The number of strands within a wire:

5. The amount of current flowing through the wire.

For this experiment, the factors which will be tested and measured

will be the length of the wire, the material of which the wire is made

from to see whether it affects the resistance, and seeing whether the

variable resistor also affects the wire in any way.

Apparatus

* Power pack

* 9 strands of copper wire, 0.193 mm thick, 30 cm long.

* 9 strands of nichrone wire, 0.193 mm thick, 30 cm long.

* 9 strands of constantan wire, 0.193 mm thick, 30 cm long.

* Ammeter, 10 amps max.

* Voltmeter, 20 volts max.

* Variable resister

* Heat proof matt.

* 7 wire leads.

* 2 crocodile clips.

* Ruler.

* Scissors.

Diagram:

Method

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Firstly collect all the apparatus needed to complete the investigation

and set the right apparatus into the correct positions.

Start of by measuring the volts and amps of one of the wires at a low

resistance, whilst always keeping the current the same for each time

at 6v. This wire should be 30 cm to start of with. When the volts and

amps have been measured, switch off the power pack between each

measurement so that the current is cut off. When this is done, cut off

5 cm of the wire and measure the volts and amps of the now 15 cm long

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