How the Length of a Wire Affects its Resistance
How the Length of a Wire Affects Its Resistance
In my physics coursework I am going to investigate the effect of the length of a wire on its resistance. Resistance is the measure of how easy it is for current to flow through a wire. Current is the rate of flow of charge through a conductor, and it is measured in amps using an ammeter.
To help me plan my investigation I have completed a preliminary experiment in which I investigated the effect of the thickness of a wire on its resistance, using three constantan wires and one copper wire. I found that the resistance increased as the thickness of the wire decreased, however, when I did the test with the copper wire I found that it was so unresistant that there would not be a lot of point in conducting my experiment using a copper wire because I would not really be able to compare the results. I therefore decided to use a wire of a higher resistance; constantan, because it will allow me to get more reliable and comparable results.
Preliminary experiment results:
Wire type/diameter Resistance (W)
Copper 0.2mm 1.8 W
Constantan 0.2mm 9.1 W
Constantan 0.45mm 5 W
Constantan 0.9mm 1.8 W
Diagram:
The things that I will measure and observe are the voltage running through the wire and the current. This will allow me to calculate the resistance of the wire. To calculate the resistance of the wire I will divide the voltage (V) by the current (I), which will give me the resistance in ohms (W).
Equipment:
The equipment that I will use is:
- power pack
- ammeter
- voltmeter
- 30 SWG (diameter) constantan wire
- 1 metre ruler
- leads
- crocodile clips
Method:
This is exactly what I will do:
1) I will set up my experiment as shown in the diagram, with the ammeter connected in series and the voltmeter connected in parallel.
2) I will stretch the wire out along the metre ruler and place the crocodile clips exactly 100cm apart.
3) I will make sure that the voltmeter and ammeter are switched on, and I will then
In my physics coursework I am going to investigate the effect of the length of a wire on its resistance. Resistance is the measure of how easy it is for current to flow through a wire. Current is the rate of flow of charge through a conductor, and it is measured in amps using an ammeter.
To help me plan my investigation I have completed a preliminary experiment in which I investigated the effect of the thickness of a wire on its resistance, using three constantan wires and one copper wire. I found that the resistance increased as the thickness of the wire decreased, however, when I did the test with the copper wire I found that it was so unresistant that there would not be a lot of point in conducting my experiment using a copper wire because I would not really be able to compare the results. I therefore decided to use a wire of a higher resistance; constantan, because it will allow me to get more reliable and comparable results.
Preliminary experiment results:
Wire type/diameter Resistance (W)
Copper 0.2mm 1.8 W
Constantan 0.2mm 9.1 W
Constantan 0.45mm 5 W
Constantan 0.9mm 1.8 W
Diagram:
The things that I will measure and observe are the voltage running through the wire and the current. This will allow me to calculate the resistance of the wire. To calculate the resistance of the wire I will divide the voltage (V) by the current (I), which will give me the resistance in ohms (W).
Equipment:
The equipment that I will use is:
- power pack
- ammeter
- voltmeter
- 30 SWG (diameter) constantan wire
- 1 metre ruler
- leads
- crocodile clips
Method:
This is exactly what I will do:
1) I will set up my experiment as shown in the diagram, with the ammeter connected in series and the voltmeter connected in parallel.
2) I will stretch the wire out along the metre ruler and place the crocodile clips exactly 100cm apart.
3) I will make sure that the voltmeter and ammeter are switched on, and I will then