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Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 341 · 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 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 3 hours. How many watt-hours (Wh) are saved?
  2. 2.Which of these wastes electricity? (a) use LED lamps (b) close the fridge quickly (c) use daylight to read (d) leave fridge door open
  3. 3.True or false: to use daylight to read wastes electricity. (a) False (b) True
  4. 4.🧾 A 1000 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
  5. 5.🔍 Which is the odd one out? (a) run fans in empty rooms (b) iron one shirt at a time (c) close the fridge quickly (d) leave the TV on standby
  6. 6.Which of these wastes electricity? (a) use old filament bulbs (b) set the AC to 24 °C (c) switch off empty rooms (d) use LED lamps
  7. 7.Which of these saves electricity? (a) iron one shirt at a time (b) use old filament bulbs (c) use LED lamps (d) run fans in empty rooms
  8. 8.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
  9. 9.🧾 A 1000 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
  10. 10.True or false: to leave fridge door open saves electricity. (a) False (b) True
  11. 11.🔍 Which is the odd one out? (a) leave fridge door open (b) use old filament bulbs (c) unplug idle chargers (d) run fans in empty rooms
  12. 12.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
  13. 13.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) an oil lamp (c) an LED lamp (d) a candle
  14. 14.True or false: to iron one shirt at a time wastes electricity. (a) True (b) False
  15. 15.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 ampere (c) 1 kilowatt-hour (kWh) (d) 1 watt
  16. 16.💡 Does it save or waste electricity to close the fridge quickly? (a) wastes electricity (b) saves electricity
  17. 17.💡 Does it save or waste electricity to switch off empty rooms? (a) saves electricity (b) wastes electricity
  18. 18.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
  19. 19.Which of these saves electricity? (a) leave the TV on standby (b) iron one shirt at a time (c) switch off empty rooms (d) run fans in empty rooms
  20. 20.🧾 A 1000 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  21. 21.True or false: to close the fridge quickly saves electricity. (a) False (b) True
  22. 22.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 7 hours. How many watt-hours (Wh) are saved?
  23. 23.🧾 A 250 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
  24. 24.🔍 Which is the odd one out? (a) run fans in empty rooms (b) unplug idle chargers (c) set the AC to 24 °C (d) switch off empty rooms
  25. 25.True or false: to iron one shirt at a time saves electricity. (a) True (b) False
  26. 26.💡 Does it save or waste electricity to set the AC to 24 °C? (a) saves electricity (b) wastes electricity
  27. 27.🔍 Which is the odd one out? (a) switch off empty rooms (b) leave the TV on standby (c) leave fridge door open (d) use old filament bulbs
  28. 28.🧾 A family uses 90 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
  29. 29.🧾 A 250 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
  30. 30.🧾 A family uses 180 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
  31. 31.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 7 hours. How many watt-hours (Wh) are saved?
  32. 32.🧾 A family uses 130 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
  33. 33.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 5 hours. How many watt-hours (Wh) are saved?
  34. 34.💡 Does it save or waste electricity to unplug idle chargers? (a) wastes electricity (b) saves electricity
  35. 35.🧾 A 50 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
  36. 36.True or false: to leave the TV on standby wastes electricity. (a) True (b) False
  37. 37.True or false: to unplug idle chargers saves electricity. (a) True (b) False
  38. 38.Which of these saves electricity? (a) run fans in empty rooms (b) iron one shirt at a time (c) use old filament bulbs (d) unplug idle chargers
  39. 39.Which of these saves electricity? (a) use daylight to read (b) iron one shirt at a time (c) leave fridge door open (d) use old filament bulbs
  40. 40.Which of these wastes electricity? (a) unplug idle chargers (b) run fans in empty rooms (c) switch off empty rooms (d) use LED lamps

Answer key

  1. 189
  2. leave fridge door open
  3. False
  4. 10
  5. close the fridge quickly
  6. use old filament bulbs
  7. use LED lamps
  8. 765
  9. 5
  10. False
  11. unplug idle chargers
  12. 459
  13. an LED lamp
  14. True
  15. 1 kilowatt-hour (kWh)
  16. saves electricity
  17. saves electricity
  18. 136
  19. switch off empty rooms
  20. 2
  21. True
  22. 595
  23. 2
  24. run fans in empty rooms
  25. False
  26. saves electricity
  27. switch off empty rooms
  28. 720
  29. 1
  30. 1440
  31. 441
  32. 780
  33. 170
  34. saves electricity
  35. 0.25
  36. True
  37. True
  38. unplug idle chargers
  39. use daylight to read
  40. run fans in empty rooms

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