Science 9 · Unit 9: Electricity · Cambridge Lower Secondary Science Stage 9

Questions

1. 1. What is the unit of resistance?

   • volts (V)
   • ohms (Ω)
   • joules (J)
   • amps (A)
   Check

2. 2. What happens to the current in a circuit when the resistance increases?

   • It decreases.
   • It increases.
   • It stays the same.
   Check

3. 3. Which equation relates resistance to voltage and current?

   • resistance = voltage + current
   • resistance = current ÷ voltage
   • resistance = voltage × current
   • resistance = voltage ÷ current
   Check

4. 4. The voltage across a resistor is 12 V and the current is 4 A. What is the resistance?

   • 16 Ω
   • 48 Ω
   • 3 Ω
   • 0.33 Ω
   Check

5. 5. The voltage across R1 is 6 V and the current is 2 A. What is its resistance?

   • 8 Ω
   • 0.33 Ω
   • 3 Ω
   • 12 Ω
   Check

6. 6. The voltage across R2 is 12 V and the current is 1 A. What is its resistance?

   • 13 Ω
   • 0.083 Ω
   • 12 Ω
   • 1 Ω
   Check

7. 7. The voltage across R3 is 6 V and the current is 0.2 A. What is its resistance?

   • 1.2 Ω
   • 30 Ω
   • 0.03 Ω
   • 3 Ω
   Check

8. 8. A 10 Ω resistor has 3 A through it. What does the voltmeter across it read?

   • 30 V
   • 3.3 V
   • 13 V
   • 0.3 V
   Check

9. 9. A 12 Ω resistor has 2 A through it. What does the voltmeter across it read?

   • 14 V
   • 24 V
   • 6 V
   • 0.17 V
   Check

10. 10. A 0.5 Ω resistor has 0.1 A through it. What does the voltmeter across it read?

    • 0.6 V
    • 0.05 V
    • 0.2 V
    • 5 V
    Check

11. 11. A 15 Ω resistor has 30 V across it. What does the ammeter read?

    • 450 A
    • 45 A
    • 0.5 A
    • 2 A
    Check

12. 12. A 0.4 Ω resistor has 4 V across it. What does the ammeter read?

    • 4.4 A
    • 0.1 A
    • 1.6 A
    • 10 A
    Check

13. 13. A 0.1 Ω resistor has 0.5 V across it. What does the ammeter read?

    • 0.2 A
    • 0.6 A
    • 5 A
    • 0.05 A
    Check

14. 14. What does I stand for in Ohm's law, V = IR?

    • current
    • resistance
    • voltage
    • energy
    Check

15. 15. In V = IR, as R increases and I stays the same, what happens to V?

    • It increases.
    • It decreases.
    • It stays the same.
    Check

16. 16. In V = IR, as R increases and V stays the same, what happens to I?

    • It increases.
    • It decreases.
    • It stays the same.
    Check

17. 17. A resistor in series with a cell carries a current. An identical resistor is added in series. What happens to the current?

    • It halves.
    • It doubles.
    • It stays the same.
    Check

18. 18. A 25 cm copper wire is in a circuit. What is its resistance most likely to be?

    • 1000 Ω
    • 100 000 Ω
    • 10 Ω
    • 0.001 Ω
    Check