An Investigation into Factors Affecting Resistance of a Wire

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An Investigation into Factors Affecting Resistance of a Wire


The possible variables I could use to find out factors affecting

resistance are material wire is made of, length of wire, temperature

and cross sectional area of wire. I will use cross sectional area of

wire and length of wire because I think it will be hard to draw

conclusions from the material of wire. I am not doing temperature

because it would be hard to get results from and I think they wouldn't

be as accurate.

I will set up a circuit to find out how length and cross sectional

area affect resistance.

I will need the following components in my circuit to gather all of

the necessary results:

· Component holder- So I can change the wire that I am testing.

· Voltmeter- Measuring potential difference across the wire, it will

have to be across the wire and not just anywhere in the circuit so it

is measuring the P.D across the wire I am testing only.

· Ammeter - measuring current of the circuit, with his and the

voltmeter I will be able to work put resistance (R=V/I). As a safety

consideration I will keep the Current under 0.5 amps, so the wire

doesn't get too hot.

· Rheostat- So I can vary the voltage in the circuit to take two

readings for each wire at different voltages, I will work out an

average of the two to reduce the margin of error.

· Switch- A safety consideration, so the wire doesn't overheat and

burn if the circuit is left on for too long.

I have decided to test length of wire at, 10cm, 30cm, 50cm, 70cm,

90cm, 110cm, 130cm, 150cm and 170cm keeping a constant cross sectional

area of 0.028mm2. I will test cross sectional area at the Cross

sectional areas of wire: 0.028 mm2, 0.045 mm2, 0.057 mm2, 0.113 mm2,

0.166 mm2 and 0.246 mm2, keeping a constant length of 50cm. My

preliminary work reviled that these were the best constants, and

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