Investigating Factors Affecting Resistance of a Wire

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Investigating Factors Affecting Resistance of a Wire

Aim

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Investigate what factors affect the resistance of wire, however in

this experiment I am going to monitor how the length of a wire affects

the resistance of a wire if the current is kept the same.

Method

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1) Arrange apparatus as shown in the Diagram:

2) Cut a length of wire over a meter long and sellotape to a meter

ruler.

3) Attach one positive crocodile clip to 0cm, and move the negative

up/down, stopping at;

5cm

10 cm

15 cm

20 cm

25 cm

30 cm

4) Attach the wire to the crocodile-clip leads and set voltage to 1

5) Other variables such as voltage, diameter of wire and

temperature will be kept constant.

6) Take the reading from the ammeter and record in results table.

(trying to keep the volt reading the same at all times, adjusts using

the variable resistor)

5) Repeat 3 times for each length of wire and find the average.

6) Then work out the resistance using the formula V÷I=R

(Voltage ÷ Current = Resistance)

Apparatus

Power Pack

Constantan wire

Leads

Voltmeter

Ammeter

Crocodile clips

1-meter ruler

Variable resistor

Fair test:

To make this fair test I kept some of the things constant. Variables

kept constant are the temperature (did experiment on the same day),

thickness/diameter 32 standard weight gage (swg), use same type of

material (nichrome), current (using variable resistor).

There was one thing I had to change during the experiment; this was

the length of the wire. Temperature has an affect on the experiment as

the voltage has control over the temperature. The more the temperature

increases the more the particles vibrate leading to a reduction in

output voltage although not by a huge amount this does have an affect.

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