RP5 resistivity of a wire

• equipment:

  • wire
  • voltmeter
  • ammeter
  • power supply
  • micrometer
  • ruler
• method:

  • measure d with micrometer at several points and angles, calculate a mean
  • set up apparatus
  • adjust l to 0.1m using crocodile clips and ruler
  • record current and voltage
  • increase l by 0.1m and repeat, until l = 0.8m
  • repeat everything twice, find mean resistance for each current
• safety:

  • disconnect circuit in between measurements to prevent the wires from heating up
  • wear goggles if any wires are tight in case they snap
  • if current gets too high, reduce voltage using power supply
• improvements:

  • use the straightest wire possible to make the length measurement more accurate
  • disconnect the wire between measurements to stop the resistance from changing