Part 1: How wire's resistance depends on its length

• What is the first step in the practical procedure?

  Set-up circuit
• What is the second step in the practical procedure?

  Attach resistance wire to metre rule
• What should be done after moving the crocodile clip?

  Take measurements for voltage and current
• How do you calculate resistance in this experiment?

  Calculate resistance for each length
• What two types of meters are needed in the circuit?

  Voltmeter and ammeter
• How should the voltmeter be connected in the circuit?

  Connected in parallel to the resistance wire
• How should the ammeter be connected in the circuit?

  Connected in series with the resistance wire
• What equation is used to obtain resistance?

  R = V/I
• What should the graph of resistance against length look like?

  It should produce a straight line through the origin
• Why might the line produced not pass through the origin?

  There may be a zero error
• Why should the wire used be thin?

  Thinner wire has higher resistance
• Why should a low potential difference be used in the experiment?

  To prevent the current from getting too high
• What issue arises if the wire heats up during the experiment?

  Resistance increases with temperature
• Why does resistance increase with temperature?

  Metal ions vibrate more and collide with electrons
• What safety precautions should be taken during the experiment?

  • Avoid touching the wire as it may be hot
  • Keep potential difference values low to prevent overheating