To investigate how the resistance of a wire varies with its length.

Repeat this with all the different lengths on the wire. Also on the experiment make sure that you read the meter from directly in front by using parallax. Another thing makes sure that the needle is not moving around this then makes the measurement correct.

Fair Test:

 To make this a fair test I’m going to keep everything the same in each test apart from the length of wire. The wire will be the same thickness and material every time.

Safety:

It’s important that the wire does not get to hot that it burns. To prevent this from happening I won’t let the current go any higher than 2amps.

Preliminary work:

We decided not to use a current of 2 Amps because it melts the wire. The other thing was we decided not use 90CM because one of the readings was off the scale.

Practical Results:

Our meter read 0.1V even when no circuit was connected so I had to take this reading off all the results which is why there is a corrected column.

Conclusion:

I have noticed that as the length of the wire increases the resistance also increases. This happens because:

This all happens because the resistance has doubled like I said in my prediction. I checked this by looking on my graph

E.g. 20CM= 0.44

      40CM=0.88

      80CM=1.76

See each time it has doubled.

Evaluation:

We found out that there was an error in our voltmeter which meant our first point was on 0.1. This made our results incorrect which meant we had to re calculate the numbers.

We read all our results to one decimal point instead of two.

I have an Anomalous point at 20cm. I can see from my results there was a error at 15amps. If I ignore this result and take an average of 0.5+1.0amps I get a point that lies on my line. I have shown this on my graph in red. This error accrued by reading the metre wrong.