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Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 725 · 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.Which of these wastes electricity? (a) unplug idle chargers (b) use LED lamps (c) iron one shirt at a time (d) use daylight to read
  2. 2.🧾 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?
  3. 3.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) an LED lamp (c) a filament bulb (d) a candle
  4. 4.💡 Does it save or waste electricity to unplug idle chargers? (a) saves electricity (b) wastes electricity
  5. 5.💡 Does it save or waste electricity to run fans in empty rooms? (a) wastes electricity (b) saves electricity
  6. 6.🧾 A 2000 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
  7. 7.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
  8. 8.Which of these saves electricity? (a) iron one shirt at a time (b) switch off empty rooms (c) use old filament bulbs (d) leave the TV on standby
  9. 9.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
  10. 10.Which of these wastes electricity? (a) set the AC to 24 °C (b) use daylight to read (c) use old filament bulbs (d) use LED lamps
  11. 11.🧾 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?
  12. 12.🧾 A 500 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
  13. 13.True or false: to run fans in empty rooms wastes electricity. (a) False (b) True
  14. 14.🧾 A family uses 60 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
  15. 15.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 5 hours. How many watt-hours (Wh) are saved?
  16. 16.Which of these wastes electricity? (a) set the AC to 24 °C (b) close the fridge quickly (c) leave the TV on standby (d) use daylight to read
  17. 17.🔍 Which is the odd one out? (a) switch off empty rooms (b) run fans in empty rooms (c) unplug idle chargers (d) close the fridge quickly
  18. 18.True or false: to use daylight to read wastes electricity. (a) True (b) False
  19. 19.🔍 Which is the odd one out? (a) leave fridge door open (b) iron one shirt at a time (c) leave the TV on standby (d) use daylight to read
  20. 20.💡 Does it save or waste electricity to leave fridge door open? (a) saves electricity (b) wastes electricity
  21. 21.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 kilowatt-hour (kWh) (c) 1 watt (d) 1 volt
  22. 22.🧾 A 100 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
  23. 23.Which of these saves electricity? (a) use old filament bulbs (b) use LED lamps (c) leave the TV on standby (d) leave fridge door open
  24. 24.🧾 A 200 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
  25. 25.💡 Does it save or waste electricity to close the fridge quickly? (a) wastes electricity (b) saves electricity
  26. 26.🔍 Which is the odd one out? (a) close the fridge quickly (b) iron one shirt at a time (c) switch off empty rooms (d) use LED lamps
  27. 27.🧾 A 50 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
  28. 28.🧾 A family uses 180 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
  29. 29.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
  30. 30.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
  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 5 hours. How many watt-hours (Wh) are saved?
  32. 32.🧾 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?
  33. 33.🧾 A family uses 140 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
  34. 34.True or false: to unplug idle chargers saves electricity. (a) False (b) True
  35. 35.True or false: to leave the TV on standby wastes electricity. (a) True (b) False
  36. 36.True or false: to unplug idle chargers wastes electricity. (a) False (b) True
  37. 37.🧾 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?
  38. 38.🧾 A family uses 190 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
  39. 39.Which of these wastes electricity? (a) use daylight to read (b) leave fridge door open (c) switch off empty rooms (d) use LED lamps
  40. 40.🧾 A 2000 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =

Answer key

  1. iron one shirt at a time
  2. 255
  3. an LED lamp
  4. saves electricity
  5. wastes electricity
  6. 16
  7. wastes electricity
  8. switch off empty rooms
  9. wastes electricity
  10. use old filament bulbs
  11. 126
  12. 2.5
  13. True
  14. 420
  15. 425
  16. leave the TV on standby
  17. run fans in empty rooms
  18. False
  19. use daylight to read
  20. wastes electricity
  21. 1 kilowatt-hour (kWh)
  22. 1
  23. use LED lamps
  24. 1.2
  25. saves electricity
  26. iron one shirt at a time
  27. 0.2
  28. 1080
  29. saves electricity
  30. saves electricity
  31. 315
  32. 136
  33. 560
  34. True
  35. True
  36. False
  37. 189
  38. 1520
  39. leave fridge door open
  40. 8

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