resistance

• What is the focus of the practical described in the video?

  Factors affecting the resistance of electrical circuits
• What equipment is used in the resistance practical?

  Battery, ammeter, voltmeter, wire
• What does the ammeter measure in the circuit?

  Current
• What does the voltmeter measure in the circuit?

  Potential difference
• How do you calculate resistance in the circuit?

  Resistance = Potential difference / Current
• What factor are we focusing on to see how resistance changes?

  Length of the wire
• How do you increase the length of the wire in the experiment?

  Move the crocodile clips further apart
• What does a straight line graph through zero indicate about resistance and wire length?

  Resistance is directly proportional to length
• What is a zero error in the context of this experiment?

  A reading when the value should be zero
• Why is zero error considered a systematic error?

  It cannot be reduced by repeating measurements
• How should you adjust readings to account for zero error?

  Subtract the zero error from all readings
• What causes zero error in this experiment?

  Contact resistance and crocodile clip positioning
• How does heating affect resistance in the wire?

  Increased temperature raises resistance
• What can be done to reduce heating effects in the wire?

  Use a low potential difference
• When should the current be turned on during the experiment?

  Only when taking a reading
• What is a variable resistor used for in a circuit?

  To control the potential difference
• How does a variable resistor change resistance?

  By changing the length of wire in a coil
• What happens to the lamp when resistance is increased using a variable resistor?

  The lamp becomes dimmer
• What are the key steps in investigating resistance in a circuit?

  1. Set up the circuit with a battery, ammeter, voltmeter, and wire.
  2. Measure current and potential difference.
  3. Calculate resistance using the formula.
  4. Change the length of the wire using crocodile clips.
  5. Record the resistance and plot a graph.
• What are the main issues to consider in the resistance practical?

  • Zero error: reading when it should be zero
  • Heating effects: increased temperature raises resistance
  • Solutions: use low potential difference, turn off current between readings