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Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 71 · 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) False (b) True
  2. 2.True or false: to switch off empty rooms saves electricity. (a) True (b) False
  3. 3.Which of these saves electricity? (a) leave the TV on standby (b) leave fridge door open (c) run fans in empty rooms (d) switch off empty rooms
  4. 4.🔍 Which is the odd one out? (a) run fans in empty rooms (b) close the fridge quickly (c) set the AC to 24 °C (d) use daylight to read
  5. 5.Which of these wastes electricity? (a) run fans in empty rooms (b) unplug idle chargers (c) use LED lamps (d) switch off empty rooms
  6. 6.🧾 A family uses 170 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
  7. 7.🧾 A family uses 110 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
  8. 8.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
  9. 9.True or false: to run fans in empty rooms saves electricity. (a) True (b) False
  10. 10.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
  11. 11.🔍 Which is the odd one out? (a) use old filament bulbs (b) leave the TV on standby (c) iron one shirt at a time (d) close the fridge quickly
  12. 12.True or false: to use daylight to read wastes electricity. (a) True (b) False
  13. 13.🧾 A 200 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
  14. 14.Which of these saves electricity? (a) unplug idle chargers (b) leave fridge door open (c) leave the TV on standby (d) use old filament bulbs
  15. 15.Which of these saves electricity? (a) run fans in empty rooms (b) use daylight to read (c) leave the TV on standby (d) iron one shirt at a time
  16. 16.🧾 A family uses 30 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  17. 17.🧾 A family uses 40 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
  18. 18.Which of these saves electricity? (a) close the fridge quickly (b) iron one shirt at a time (c) run fans in empty rooms (d) leave the TV on standby
  19. 19.🧾 Which lamp gives the same light for the least power? (a) a candle (b) an oil lamp (c) a filament bulb (d) an LED lamp
  20. 20.🧾 One “unit” on an electricity bill is … (a) 1 kilowatt-hour (kWh) (b) 1 volt (c) 1 watt (d) 1 ampere
  21. 21.Which of these wastes electricity? (a) unplug idle chargers (b) switch off empty rooms (c) iron one shirt at a time (d) use daylight to read
  22. 22.🧾 A 50 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
  23. 23.Which of these saves electricity? (a) leave fridge door open (b) use old filament bulbs (c) iron one shirt at a time (d) use LED lamps
  24. 24.🧾 A 500 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
  25. 25.🧾 A 2000 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  26. 26.💡 Does it save or waste electricity to unplug idle chargers? (a) saves electricity (b) wastes electricity
  27. 27.🧾 A 250 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
  28. 28.🔍 Which is the odd one out? (a) iron one shirt at a time (b) leave the TV on standby (c) use old filament bulbs (d) switch off empty rooms
  29. 29.🧾 A 1500 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
  30. 30.💡 Does it save or waste electricity to set the AC to 24 °C? (a) saves electricity (b) wastes electricity
  31. 31.🔍 Which is the odd one out? (a) close the fridge quickly (b) unplug idle chargers (c) use daylight to read (d) leave fridge door open
  32. 32.🧾 A 50 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  33. 33.🧾 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?
  34. 34.True or false: to leave fridge door open wastes electricity. (a) False (b) True
  35. 35.💡 Does it save or waste electricity to switch off empty rooms? (a) saves electricity (b) wastes electricity
  36. 36.💡 Does it save or waste electricity to leave fridge door open? (a) saves electricity (b) wastes electricity
  37. 37.🧾 A 1500 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  38. 38.Which of these saves electricity? (a) use old filament bulbs (b) leave the TV on standby (c) set the AC to 24 °C (d) run fans in empty rooms
  39. 39.🧾 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?
  40. 40.True or false: to iron one shirt at a time saves electricity. (a) True (b) False

Answer key

  1. False
  2. True
  3. switch off empty rooms
  4. run fans in empty rooms
  5. run fans in empty rooms
  6. 850
  7. 440
  8. saves electricity
  9. False
  10. wastes electricity
  11. close the fridge quickly
  12. False
  13. 0.8
  14. unplug idle chargers
  15. use daylight to read
  16. 270
  17. 280
  18. close the fridge quickly
  19. an LED lamp
  20. 1 kilowatt-hour (kWh)
  21. iron one shirt at a time
  22. 0.2
  23. use LED lamps
  24. 2
  25. 4
  26. saves electricity
  27. 2
  28. switch off empty rooms
  29. 12
  30. saves electricity
  31. leave fridge door open
  32. 0.1
  33. 126
  34. True
  35. saves electricity
  36. wastes electricity
  37. 3
  38. set the AC to 24 °C
  39. 357
  40. False

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