Resistivity Ω = Voltage V
_________
Current A
I think the length of the wire is directly proportional to resistance. So that as the length doubles so does the resistance.
Aim: In this experiment, the aim is to find out what the link is between the potential difference of a wire of constant length (wire 2) and the length of a wire of varying length (wire 1).
Diagram:
Hypothesis: I predict that as wire 1 gets longer, the P.d across wire 2 will decrease. This will occur because the length is increased, which means the electrons will need a greater original voltage to be able to travel the new length, and this will lead to a decrease as the electrons loose energy as the move. They will loose energy because the resistivity of wire 1 has increased and the electrons will loose energy as they move along the wires.
Apparatus: Cell Volt meter
Nichrome wires Ruler
Crocodile clips
Safety: To make this experiment safe, I will not short circuit the battery, and also I will check the circuit before completing it.
Method:
- Take a 2V cell and connect it to wire 1 at point A on the above diagram using crocodile clips.
- Measure the length of wire 1 using the ruler
- Connect wire 1 to wire 2 at point B on the above diagram using crocodile clips
- Attach wire 2 to the cell at point C on the above diagram again using crocodile clips
- Attach the volt meter to points B and C
- Note the reading of the meter on the table below
- Change the length of wire 1 and reattach the wire into the circuit
- Note down the new length and new voltage
- Repeat the above steps for at least 10 times, to obtain a more accurate set of results for drawing the graph
- Draw a graph and plot the results obtained using the results table below.
Results:
Conclusion:
As you can see from above, the results I obtained prove that the prediction I gave was correct.
Graph: See attached sheet
Evaluation:
The experiment went well, but I think that I could improve the experiment by having a more sensitive voltmeter and also by having a more powerful cell. From the results I have acquired, I was able to produce a reliable conclusion, which supports my theory in my prediction that as the length of the wire increases, the potential difference increases, and so does the resistance. I think my results are fairly reliable, as they are closely correlated to the line of best fit I have drawn. Also my graph proves that the results had little flaws due to the line of best fit and they also confirm my predictions.
