Resistance of a Wire

APPARATUS:

ؠAmmeter- measure the current of the circuit

ؠVoltmeter- to measure the voltage of the circuit

ؠConstant wire

ؠBattery pack

ؠMeter ruler

ؠWires

ؠCrocodile clips

ؠMicrometer

To record and measure the resistance I will use an Ammeter to measure the current in amps and a voltmeter to measure the voltage in volts. I will work out resistance in ohms by using Ohms Law which is the formula shown below:

R = V ЃЂ I

Resistance (in Ñ"¶) = Voltage (in Volts) ЃЂ Current (in Amps)

ANALYSIS

The results from the table and from the graph show how the resistance compares to the length of the wire. From my graph it is clearly seen that there is a very positive correlation, this shows that the longer the wire the higher the resistance, the results obtained are directly proportional, I can see this if I do a couple of simple calculations. I will take the average resistance for 40cm wire and the average of resistance of the wire twice the length i.e. 80cm.

Resistance of wire of 40cm = 1.8 Ohms

Resistance of wire of 80cm = 3.63 Ohms

3.63 / 1.8 = 2.016 ohms

The resistance of 80cm wire is double the resistance of 40cm wire. This proves my prediction where I said that the longer the wire the greater the resistance, and it also proves what I said about the results being directly proportional ie if the wire is twice as long the resistance is twice as great.

The line of best fit on my graph shows that the results have followed the expected pattern. The points are very close to the line of best fit or even touching it. This showed that the results were directly proportional throughout the experiment, as the line does not curve suddenly or curve or bend at all in any way, as the gradient of the line stayed the same throughout.

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