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11th grade Electric power and the energy a home uses worksheet

6 printable versionsBuilding Confidence10 questions · answer keyFree · no account

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Electric power and the energy a home uses

Grade 11 Science Worksheet - Building Confidence

NameDate

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

  1. Ari checks a heater element: 120 V across a 24 Ω resistance. How many watts does it use?

  2. Bo checks a toaster element: 120 V across a 9.6 Ω resistance. How many watts does it use?

  3. Esme checks a small car heater: 12 V across a 1.2 Ω resistance. How many watts does it use?

  4. Luz compares a 1.0 kW microwave with a 1,200 W toaster. Which has the greater power?

    • The toaster: 1.0 kW is only 1,000 W
    • The microwave, since a kilowatt is bigger than a watt
    • They are equal, since both labels give power
    • The microwave, since 1.0 kW is 10,000 W

  5. Milo runs a 60 W bulb for 5.0 h. How much energy does it use?

    • 0.30 kW, a power unit for an energy
    • 300 Wh, which is 0.30 kWh
    • 12 Wh, from 60 ÷ 5.0
    • 3.0 kWh

  6. A home uses 450 kWh in a month. How many joules is that, with 1 kWh = 3.6 × 10⁶ J, Noah?

    • 1.62 × 10⁶ J
    • 1.62 × 10¹² J
    • 1.25 × 10⁻⁴ J, from 450 ÷ (3.6 × 10⁶)
    • 1.62 × 10⁹ J

  7. Pia compares a 100 W bulb on for 1.0 h with a 1,000 W heater on for 0.10 h. Which uses more energy?

    • Neither: both use 100 Wh
    • The heater: 1,000 Wh against 100 Wh
    • The heater, since its power is ten times larger
    • The bulb, since it runs ten times longer

  8. A home uses 900 kWh in a 30-day month. What is its average power, Ren?

    • 30 kW, from 900 ÷ 30
    • 27,000 kW, from 900 × 30
    • 1.25 kW
    • 0.8 kW, from 720 ÷ 900

  9. Tala compares a 1,500 W heater run 4 h a day with a 150 W computer run 8 h a day, for 30 days. Which uses more energy?

    • The heater: 6,000 kWh, from 1,500 × 4
    • The computer, since it runs longer each day
    • The heater: 180 kWh, against 36 kWh
    • They use the same, since both are plugged in

  10. Zee runs a 1.5 kW oven for 40 minutes. How much energy does it use?

    • 0.04 kWh, from 1.5 ÷ 40
    • 1.0 kWh
    • 60 kWh, from 1.5 × 40
    • 1.5 kWh, the power as the energy
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11th grade Electric power and the energy a home uses worksheet – printable
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About this worksheet

Electric power and energy use. Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

  • I can find power from P = V²/R and P = IV, current from P ÷ V, and check a circuit against its breaker (P = I × V, with loads adding).
  • I can find energy in kWh from watts and minutes for several appliances, add standby power over the idle hours, and price it.
  • I can compare bulbs and refrigerators by light per watt, life-cycle cost and payback, and compare designs over their lifetime.
  • I can use P = I²R to explain why high-voltage lines lose less, find the energy a kettle needs with efficiency, follow a fuel-to-home chain, and judge claims about a home's energy use.

Standard: none (TX, FL)

Words to know

power: How fast energy is used, in watts

kilowatt-hour (kWh): Energy used by 1 kW for 1 hour

standby power: Power a device still draws when it is off or idle

I²R heating: Heat made in a wire: current squared times resistance

payback time: How long savings take to repay a higher price

Common mistakes

Your child found the current V ÷ R but stopped there. Power also multiplies by the voltage.

Your child multiplied voltage by resistance. Power is V² ÷ R, or V × I with I = V ÷ R.

Your child used minutes as if they were hours. Divide minutes by 60 to get hours.

Questions parents ask

What is the most common mistake with electric power and the energy a home uses?

Your child found the current V ÷ R but stopped there. Power also multiplies by the voltage.

Are these 11th grade science worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

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