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Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 919 · 40 questions
TalentJR

Remember (Watts × hours ÷ 1000): Units (kWh) = watts × hours ÷ 1000. Bill = units × price per unit (e.g. 150 units × ₹6 = ₹900). Save: switch off, LED lamps, daylight, no standby, close the fridge quickly.

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  1. 1.🧾 A 100 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  2. 2.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) an LED lamp (c) a candle (d) a filament bulb
  3. 3.Which of these saves electricity? (a) unplug idle chargers (b) leave the TV on standby (c) iron one shirt at a time (d) run fans in empty rooms
  4. 4.True or false: to use LED lamps wastes electricity. (a) False (b) True
  5. 5.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 5 hours. How many watt-hours (Wh) are saved?
  6. 6.Which of these wastes electricity? (a) unplug idle chargers (b) switch off empty rooms (c) use old filament bulbs (d) close the fridge quickly
  7. 7.🧾 A 500 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
  8. 8.🧾 A family uses 120 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
  9. 9.True or false: to switch off empty rooms wastes electricity. (a) True (b) False
  10. 10.🧾 A 500 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
  11. 11.🔍 Which is the odd one out? (a) leave the TV on standby (b) use daylight to read (c) run fans in empty rooms (d) iron one shirt at a time
  12. 12.True or false: to use old filament bulbs wastes electricity. (a) True (b) False
  13. 13.🔍 Which is the odd one out? (a) leave the TV on standby (b) close the fridge quickly (c) use old filament bulbs (d) run fans in empty rooms
  14. 14.💡 Does it save or waste electricity to unplug idle chargers? (a) wastes electricity (b) saves electricity
  15. 15.🧾 A 1000 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
  16. 16.True or false: to leave fridge door open wastes electricity. (a) False (b) True
  17. 17.True or false: to use daylight to read wastes electricity. (a) True (b) False
  18. 18.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
  19. 19.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 ampere (c) 1 kilowatt-hour (kWh) (d) 1 volt
  20. 20.💡 Does it save or waste electricity to use old filament bulbs? (a) saves electricity (b) wastes electricity
  21. 21.True or false: to leave the TV on standby wastes electricity. (a) True (b) False
  22. 22.🧾 A family uses 100 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
  23. 23.Which of these wastes electricity? (a) leave the TV on standby (b) use daylight to read (c) switch off empty rooms (d) unplug idle chargers
  24. 24.True or false: to run fans in empty rooms saves electricity. (a) False (b) True
  25. 25.🧾 A 1000 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
  26. 26.True or false: to use daylight to read saves electricity. (a) True (b) False
  27. 27.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 2 hours. How many watt-hours (Wh) are saved?
  28. 28.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 8 hours. How many watt-hours (Wh) are saved?
  29. 29.Which of these saves electricity? (a) switch off empty rooms (b) iron one shirt at a time (c) leave fridge door open (d) run fans in empty rooms
  30. 30.Which of these saves electricity? (a) leave the TV on standby (b) iron one shirt at a time (c) set the AC to 24 °C (d) run fans in empty rooms
  31. 31.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
  32. 32.🧾 A 50 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
  33. 33.🧾 A 50 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
  34. 34.Which of these saves electricity? (a) leave fridge door open (b) leave the TV on standby (c) use daylight to read (d) run fans in empty rooms
  35. 35.True or false: to leave fridge door open saves electricity. (a) False (b) True
  36. 36.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 1 hour. How many watt-hours (Wh) are saved?
  37. 37.🧾 A family uses 80 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
  38. 38.🧾 A 2000 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
  39. 39.True or false: to run fans in empty rooms wastes electricity. (a) False (b) True
  40. 40.True or false: to iron one shirt at a time saves electricity. (a) True (b) False

Answer key

  1. 0.2
  2. an LED lamp
  3. unplug idle chargers
  4. False
  5. 255
  6. use old filament bulbs
  7. 5
  8. 480
  9. False
  10. 2
  11. use daylight to read
  12. True
  13. close the fridge quickly
  14. saves electricity
  15. 10
  16. True
  17. False
  18. saves electricity
  19. 1 kilowatt-hour (kWh)
  20. wastes electricity
  21. True
  22. 600
  23. leave the TV on standby
  24. False
  25. 4
  26. True
  27. 126
  28. 408
  29. switch off empty rooms
  30. set the AC to 24 °C
  31. wastes electricity
  32. 0.5
  33. 0.3
  34. use daylight to read
  35. False
  36. 63
  37. 560
  38. 20
  39. True
  40. False

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