Circuits

• What is the purpose of Core Practical 5a?

  To investigate potential difference, current, and resistance
• What equipment is used in Core Practical 5a?

  Filament lamp, ammeter, voltmeter, resistor
• How should the circuit be set up in Method Part 1 of Core Practical 5a?

  In series with a resistor, power supply, and ammeter
• What should you do immediately after turning on the power supply in Method Part 1?

  Record potential difference and current values
• Why is it important to take readings quickly in Method Part 1?

  To prevent the resistor from overheating
• What should you do after turning off the power supply in Method Part 1?

  Allow the resistor to cool to room temperature
• What does plotting current against potential difference show in Method Part 1?

  The relationship between current and potential difference
• How is resistance calculated from the gradient of the graph in Method Part 1?

  Resistance = $\frac{1}{\text{gradient}}$
• What does the constant gradient indicate about the fixed resistor?

  Its resistance does not change with potential difference
• What is the main observation when replacing the resistor with a filament lamp in Method Part 2?

  The I-V graph shows a curve that plateaus
• What happens to the resistance of a filament lamp as potential difference increases?

  The resistance increases as potential difference increases
• What equipment is used in Core Practical 5b?

  Two filament lamps, fixed resistor, ammeters, voltmeters
• What is the first step in Method Part 1 of Core Practical 5b?

  Set up a series circuit as shown in Circuit 1
• What should you do after starting the power supply in Method Part 1 of Core Practical 5b?

  Record values for V1, V2, V3, and A1
• What should be true for V2 + V3 in Method Part 1 of Core Practical 5b?

  It should equal V1 for each voltage
• What is the first step in Method Part 2 of Core Practical 5b?

  Set up a parallel circuit as shown in Circuit 2
• What should you ensure about A3 and A4 in Method Part 2 of Core Practical 5b?

  A3 should equal A4, and their sum equals A2
• What should be true for V4, V5, and V6 in Method Part 2 of Core Practical 5b?

  They should all be the same voltage
• What is a safety precaution when changing the circuit?

  Turn off the power supply to reduce shock risk
• Why should you not touch the filament lamp after use?

  It can cause burns due to heat