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Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 151 · 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.True or false: to switch off empty rooms wastes electricity. (a) True (b) False
  2. 2.True or false: to close the fridge quickly wastes electricity. (a) False (b) True
  3. 3.True or false: to leave fridge door open wastes electricity. (a) True (b) False
  4. 4.Which of these wastes electricity? (a) leave the TV on standby (b) close the fridge quickly (c) switch off empty rooms (d) unplug idle chargers
  5. 5.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 volt (c) 1 kilowatt-hour (kWh) (d) 1 watt
  6. 6.🧾 A family uses 150 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  7. 7.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 3 hours. How many watt-hours (Wh) are saved?
  8. 8.Which of these wastes electricity? (a) set the AC to 24 °C (b) unplug idle chargers (c) run fans in empty rooms (d) use daylight to read
  9. 9.True or false: to close the fridge quickly saves electricity. (a) False (b) True
  10. 10.Which of these wastes electricity? (a) switch off empty rooms (b) iron one shirt at a time (c) use daylight to read (d) close the fridge quickly
  11. 11.💡 Does it save or waste electricity to leave the TV on standby? (a) saves electricity (b) wastes electricity
  12. 12.🧾 A 200 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  13. 13.🧾 A family uses 80 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
  14. 14.Which of these saves electricity? (a) leave fridge door open (b) run fans in empty rooms (c) close the fridge quickly (d) use old filament bulbs
  15. 15.🧾 A family uses 90 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
  16. 16.🧾 A 1500 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
  17. 17.True or false: to use LED lamps saves electricity. (a) True (b) False
  18. 18.Which of these saves electricity? (a) set the AC to 24 °C (b) use old filament bulbs (c) leave the TV on standby (d) run fans in empty rooms
  19. 19.Which of these saves electricity? (a) iron one shirt at a time (b) switch off empty rooms (c) use old filament bulbs (d) run fans in empty rooms
  20. 20.🔍 Which is the odd one out? (a) iron one shirt at a time (b) switch off empty rooms (c) leave the TV on standby (d) run fans in empty rooms
  21. 21.True or false: to leave fridge door open saves electricity. (a) False (b) True
  22. 22.🧾 Which lamp gives the same light for the least power? (a) an LED lamp (b) a candle (c) an oil lamp (d) a filament bulb
  23. 23.🧾 A 2000 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
  24. 24.💡 Does it save or waste electricity to leave fridge door open? (a) saves electricity (b) wastes electricity
  25. 25.🔍 Which is the odd one out? (a) run fans in empty rooms (b) use daylight to read (c) unplug idle chargers (d) switch off empty rooms
  26. 26.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
  27. 27.💡 Does it save or waste electricity to close the fridge quickly? (a) saves electricity (b) wastes electricity
  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 6 hours. How many watt-hours (Wh) are saved?
  29. 29.🧾 A 250 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
  30. 30.True or false: to switch off empty rooms saves electricity. (a) False (b) True
  31. 31.True or false: to run fans in empty rooms saves electricity. (a) True (b) False
  32. 32.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
  33. 33.🧾 A 500 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
  34. 34.🧾 A 100 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
  35. 35.Which of these wastes electricity? (a) use daylight to read (b) switch off empty rooms (c) set the AC to 24 °C (d) use old filament bulbs
  36. 36.💡 Does it save or waste electricity to run fans in empty rooms? (a) saves electricity (b) wastes electricity
  37. 37.🔍 Which is the odd one out? (a) leave fridge door open (b) use daylight to read (c) switch off empty rooms (d) unplug idle chargers
  38. 38.🧾 A 1500 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
  39. 39.🔍 Which is the odd one out? (a) iron one shirt at a time (b) run fans in empty rooms (c) unplug idle chargers (d) leave fridge door open
  40. 40.🧾 A 200 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =

Answer key

  1. False
  2. False
  3. True
  4. leave the TV on standby
  5. 1 kilowatt-hour (kWh)
  6. 1350
  7. 153
  8. run fans in empty rooms
  9. True
  10. iron one shirt at a time
  11. wastes electricity
  12. 0.4
  13. 480
  14. close the fridge quickly
  15. 720
  16. 12
  17. True
  18. set the AC to 24 °C
  19. switch off empty rooms
  20. switch off empty rooms
  21. False
  22. an LED lamp
  23. 10
  24. wastes electricity
  25. run fans in empty rooms
  26. saves electricity
  27. saves electricity
  28. 306
  29. 1
  30. True
  31. False
  32. saves electricity
  33. 2
  34. 0.6
  35. use old filament bulbs
  36. wastes electricity
  37. leave fridge door open
  38. 15
  39. unplug idle chargers
  40. 0.8

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