resistence

• What should you be able to describe by the end of the video?

  How to investigate resistance factors
• Why is it important to learn about required practicals?

  They account for at least 15% of exam marks
• What factors are being investigated in the practical?

  • Factors affecting resistance in circuits
  • Focus on the length of a wire
• What equipment is used in the resistance investigation?

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

  Current in the circuit
• What does the voltmeter measure in the circuit?

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

  Resistance = Voltage / Current
• What is the relationship between resistance and wire length?

  Resistance is directly proportional to wire length
• How can you increase the length of the wire in the circuit?

  Move the crocodile clips further apart
• What does a straight line graph through zero indicate?

  Resistance is directly proportional to length
• What is a zero error in measurements?

  Reading when the value should be zero
• How does zero error affect resistance measurements?

  It requires subtraction from all readings
• What causes zero error in this practical?

  Difficulty positioning crocodile clips at zero
• What is the effect of heating on resistance?

  Resistance increases with temperature
• How can you 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
• How does a variable resistor work?

  • Contains a long piece of wire in a coil
  • Slider changes the length of wire in circuit
  • Controls potential difference across the load
• What happens to the lamp when resistance is increased?

  The lamp becomes dimmer
• Where can you find more questions on required practicals?

  • Vision workbook
  • Link provided in the video
• What is the main focus of the practical discussed in the video?

  Investigating factors affecting resistance