Current, voltage and resistance

Answer Key - Grade 11 Science Worksheet

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

1. 1.

   A 9 V battery drives a current through a 100 Ω resistor and a 200 Ω resistor in series. What is the voltage across the 200 Ω resistor, Ari?

   6 V
2. 2.

   A 6 V battery drives a current through a 20 Ω resistor and a 40 Ω resistor in series. What is the voltage across the 40 Ω resistor, Esme?

   4 V
3. 3.

   Kira joins each resistor in turn to a 3 V battery. What current flows through each?

   • 0.15 A through P and 0.30 A through Q
   • 0.30 A through P and 0.15 A through Q
   • 0.30 A through both, since the voltage is the same
   • 0.60 A through P and 0.30 A through Q
4. 4.

   Luz reads the bulb's graph. How does its resistance, V ÷ I, change from 0.2 A to 0.4 A?

   • It stays near 15 Ω, since it is the same bulb
   • It falls from 15 Ω to 10 Ω, since voltage rises slowly at first
   • It rises from 15 Ω to 25 Ω
   • It rises from 15 Ω to 35 Ω, the slope between the points
5. 5.

   A 20 Ω resistor is in series with a 30 Ω and a 60 Ω resistor wired in parallel, all across a 12 V battery. What current leaves the battery, Milo?

   • 0.18 A: 12 V ÷ (20 + 45) Ω, with the pair averaged
   • 0.11 A: 12 V ÷ (20 + 30 + 60) Ω, all in series
   • 0.60 A: 12 V ÷ 20 Ω, the first resistor alone
   • 0.30 A: the parallel pair makes 20 Ω, so 40 Ω in all
6. 6.

   A 20 Ω resistor is in series with a 30 Ω and a 60 Ω resistor wired in parallel across 12 V. What current flows through the 60 Ω resistor, Noah?

   • 0.10 A: the pair has 6 V across it, and 6 ÷ 60
   • 0.30 A: the total current from the battery
   • 0.20 A: 6 V ÷ 30 Ω, the other branch
   • 0.15 A: half of the total current
7. 7.

   Bulbs A (10 Ω) and B (30 Ω) are in series across a 12 V battery. Which glows brighter, and with what power, Pia?

   • They glow equally, since the same current passes through both
   • A is brighter, since a smaller resistance draws more current
   • A is brighter: 14.4 W against 4.8 W for B
   • B is brighter: 2.7 W against 0.9 W for A
8. 8.

   A battery reads 6.0 V with no load and 5.4 V while delivering 2.0 A. What is its internal resistance, Ren?

   • 0.30 Ω: (6.0 − 5.4) V ÷ 2.0 A
   • 3.0 Ω: 6.0 V ÷ 2.0 A
   • 2.7 Ω: 5.4 V ÷ 2.0 A, the load resistance
   • 0.60 Ω: the lost voltage in volts

9. Read this first

   A battery under different loads (example data)

   current (A)	terminal voltage (V)
   0.5	5.85
   1	5.7
   1.5	5.55
   2	5.4

10. 9.

    Tala fits a line to the battery table, V = ε − Ir. What emf and internal resistance does the line give?

    • 5.40 V and 0.30 Ω, using the last reading as the emf
    • 6.00 V and 0.15 Ω, using the drop in volts as r
    • 6.00 V and 0.30 Ω: V falls 0.15 V for each 0.5 A
    • 6.00 V and 2.7 Ω, using 5.4 V ÷ 2.0 A as r
11. 10.

    A 12 Ω and a 24 Ω resistor are wired in parallel across a 6 V battery. What current leaves the battery, and how does it split, Zee?

    • 0.75 A in all: 0.25 A in the 12 Ω and 0.50 A in the 24 Ω
    • 0.75 A in all: 0.50 A in the 12 Ω and 0.25 A in the 24 Ω
    • 0.38 A in all: the average of the two branch currents
    • 0.17 A in all: 6 V ÷ (12 + 24) Ω