Physics Coursework: Factors affecting resistance of a wire. Hypothesis I think that as you increase the length of the wire, you also increase the amount of resistance.

Method:

1. Collect apparatus: a voltmeter, an ammeter, 5x wires, 2 crocodile clips, 10, 20 and 40 cm of both nichrome and copper wires and a power pack.
2. Set apparatus as shown in the diagram
3. Set the power supply on a low voltage possible. (So that there is not too high a current passing through the circuit.)
4. Create a resistor by placing the ruler horizontally on the table and laying the 1 m wire on top of it use securing tape on both ends leaving just a small place to connect the voltmeter.
5. Place the end of the voltmeter at different lengths.
6. Record both the voltage and the current at each 10 cm.
7. Repeat this experiment 3 times (for accurate results) and work out the resistance for each length by using the following formula:
   Resistance (Ohms) = Voltage (v) / Current (I)
8. Then work out the average of the resistance from every length.
9. Start at 30 cm otherwise smaller lengths will overheat the wire, always use protection goggles and avoid direct contact with the hot wire.

Equipment:

• Power pack
•  Ammeter
• Voltmeter
• Crocodile clips
• 1metre ruler (made of insulating material)
• 3m of wire
• Tape

Diagram:

Independent variable

• Length of wire

Dependant variable

• Resistance

Controlled variables 

• Cross section area (thickness)
• Changing materials
• Changing temperatures

Safety:

• Set the power supply on a low voltage possible. (So that there is not too high a current passing through the circuit.)
• Use goggles to avoid direct contact with wire
• Start at 30 cm otherwise smaller lengths will overheat the wire

Table of results

Average

Conclusion

My hypothesis was correct. There is a connection between resistance and wire length, as the length of the wire increases the resistance increases. Ohm's law states that the current flowing through the circuit is directly proportional to the voltage applied. (If you double one, you double the other).