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Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 250 · 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 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
  2. 2.Which of these saves electricity? (a) use old filament bulbs (b) run fans in empty rooms (c) use LED lamps (d) leave fridge door open
  3. 3.True or false: to set the AC to 24 °C wastes electricity. (a) True (b) False
  4. 4.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 kilowatt-hour (kWh) (c) 1 ampere (d) 1 watt
  5. 5.🧾 A family uses 120 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
  6. 6.True or false: to iron one shirt at a time wastes electricity. (a) False (b) True
  7. 7.🧾 A family uses 160 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  8. 8.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 10 hours. How many watt-hours (Wh) are saved?
  9. 9.🧾 A 1000 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
  10. 10.🧾 A 200 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
  11. 11.🧾 A 60 W filament bulb is swapped for a 9 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 1000 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
  13. 13.🔍 Which is the odd one out? (a) iron one shirt at a time (b) use daylight to read (c) leave fridge door open (d) run fans in empty rooms
  14. 14.True or false: to leave fridge door open saves electricity. (a) False (b) True
  15. 15.True or false: to leave fridge door open wastes electricity. (a) False (b) True
  16. 16.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 1 hour. How many watt-hours (Wh) are saved?
  17. 17.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 7 hours. How many watt-hours (Wh) are saved?
  18. 18.True or false: to close the fridge quickly wastes electricity. (a) False (b) True
  19. 19.🧾 A 1000 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
  20. 20.🧾 A family uses 100 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  21. 21.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
  22. 22.Which of these saves electricity? (a) use old filament bulbs (b) run fans in empty rooms (c) set the AC to 24 °C (d) leave the TV on standby
  23. 23.🧾 A 2000 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
  24. 24.🧾 A family uses 70 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  25. 25.🔍 Which is the odd one out? (a) unplug idle chargers (b) use daylight to read (c) leave the TV on standby (d) close the fridge quickly
  26. 26.💡 Does it save or waste electricity to leave the TV on standby? (a) saves electricity (b) wastes electricity
  27. 27.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
  28. 28.Which of these wastes electricity? (a) use LED lamps (b) unplug idle chargers (c) switch off empty rooms (d) leave the TV on standby
  29. 29.🧾 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
  30. 30.🧾 A 1500 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
  31. 31.🧾 A 1500 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
  32. 32.🧾 A family uses 200 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
  33. 33.True or false: to unplug idle chargers wastes electricity. (a) False (b) True
  34. 34.🧾 A family uses 110 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
  35. 35.🔍 Which is the odd one out? (a) switch off empty rooms (b) leave the TV on standby (c) use old filament bulbs (d) leave fridge door open
  36. 36.🧾 A 200 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  37. 37.Which of these saves electricity? (a) run fans in empty rooms (b) close the fridge quickly (c) leave the TV on standby (d) iron one shirt at a time
  38. 38.🔍 Which is the odd one out? (a) leave the TV on standby (b) set the AC to 24 °C (c) leave fridge door open (d) run fans in empty rooms
  39. 39.Which of these saves electricity? (a) use old filament bulbs (b) leave fridge door open (c) leave the TV on standby (d) unplug idle chargers
  40. 40.🧾 A 2000 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =

Answer key

  1. 204
  2. use LED lamps
  3. False
  4. 1 kilowatt-hour (kWh)
  5. 840
  6. True
  7. 1440
  8. 340
  9. 8
  10. 1
  11. 102
  12. 5
  13. use daylight to read
  14. False
  15. True
  16. 34
  17. 357
  18. False
  19. 4
  20. 900
  21. saves electricity
  22. set the AC to 24 °C
  23. 8
  24. 630
  25. leave the TV on standby
  26. wastes electricity
  27. wastes electricity
  28. leave the TV on standby
  29. an LED lamp
  30. 12
  31. 6
  32. 1000
  33. False
  34. 660
  35. switch off empty rooms
  36. 0.4
  37. close the fridge quickly
  38. set the AC to 24 °C
  39. unplug idle chargers
  40. 4

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