Investigating wires and resistance.

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Physics coursework – investigating wires and resistance

I am going to perform an experiment to investigate the resistance of a wire.

The factors that I could change are:

  • Length of a wire
  • Voltage
  • Thickness of the wire
  • Temperature
  • Material the wire is made of

The factors I could observe are:

  • The voltage
  • The resistance
  • The temperature
  • The amps

I will keep everything constant but I will vary the length and observe the resistance.

Resistance

(Ohms)          

                Length (cm)

My prediction is that the resistance will increase in direct proportion to the length of the wire. This means that when you double the length the resistance will also double. I also predict that the line of best fit will go through the origin.

When a charge flows through a wire they get slowed down when they hit positive ions this generating a lot of heat this slowing down of electrons is called resistance. A charge is a flow of negative ions. As my wire gets longer the resistance will increase if I double the length of wire the amount of resistance will also double as there are double the amount of positive ions. The line of best fit will go through the origin because when there is no wire there cannot be any resistance.

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This is the table I will use to plot my results in:

Method:

I will attach a crocodile clip to one end of the wire and will put the other crocodile clip 10cm along the wire. I will then record readings from the ammeter and the voltmeter. I will move the wire along to measure the amps and volts at 20cm, 30cm, 40cm, 50cm, 60cm, 70cm and 80cm. After I have completed all these readings I will repeat the whole experiment take all the readings again.  

Apparatus:

  • 1m wire
  • Power ...

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