Current, voltage and resistance

Answer Key - Grade 11 Science Worksheet - Building Confidence

Circle the best answer, or write your answer on the line.

1. 1.

   A 12 V battery is joined across a 4 kΩ resistor. What current flows, in mA, Ari?

   3 mA
2. 2.

   A 5 V battery is joined across a 2.5 kΩ resistor. What current flows, in mA, Bo?

   2 mA
3. 3.

   Circuit schematic (example data): a 6 V battery, a closed switch and one resistor in one loop. Jun reads the schematic. What is the resistor's resistance?

   • 1.5 Ω: 6 V × 0.25 A
   • 24 Ω: 6 V ÷ 0.25 A
   • 5.75 Ω: 6 V − 0.25 A
   • 0.042 Ω: 0.25 A ÷ 6 V
4. 4.

   Kira reads the schematic. What does the ammeter read?

   • 0.20 A: 12 V ÷ 60 Ω, the average resistance
   • 0.10 A: 12 V ÷ (40 Ω + 80 Ω)
   • 0.15 A: 12 V ÷ 80 Ω, the second resistor alone
   • 0.30 A: 12 V ÷ 40 Ω, the first resistor alone
5. 5.

   Luz reads the schematic. What does the voltmeter across the 80 Ω resistor read?

   • 8 V: 0.10 A × 80 Ω
   • 6 V, the battery voltage shared equally
   • 4 V: 0.10 A × 40 Ω
   • 12 V, the battery voltage
6. 6.

   A 470 Ω resistor has 9.4 V across it. What current flows through it, Milo?

   • 200 mA, out by a factor of ten the other way
   • 2 mA, out by a factor of ten
   • 20 mA: 9.4 V ÷ 470 Ω = 0.020 A
   • 0.02 mA, out by a factor of 1,000
7. 7.

   A 4.7 kΩ resistor carries 2.0 mA. What voltage is across it, Noah?

   • 9,400 V: 2.0 A × 4,700 Ω
   • 9.4 V: 0.0020 A × 4,700 Ω
   • 2.35 V: 4.7 kΩ ÷ 2.0 mA
   • 0.0094 V: 0.0020 A × 4.7 Ω
8. 8.

   Why must a voltmeter have a very high resistance, Ren?

   • It must add resistance so it shares the circuit's current
   • It draws a tiny current, so it barely changes the circuit
   • It measures current, which needs a high resistance
   • It needs to handle large voltages without overheating
9. 9.

   Tala connects an ammeter across a resistor instead of in the loop. What happens?

   • A large current bypasses the resistor through the ammeter
   • The resistor carries twice the current
   • Nothing changes; the meter reads the resistor's current
   • The ammeter reads zero because no current enters it
10. 10.

    Zee reads the voltage-current graph of a resistor. What is its resistance?

    • 3.2 Ω: 8 V × 0.4 A
    • 0.05 Ω: 0.4 A ÷ 8 V
    • 8.4 Ω: 8 V + 0.4 A
    • 20 Ω: 8 V ÷ 0.4 A