Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 642 · 40 questions

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.

1. 1.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 3 hours. How many watt-hours (Wh) are saved?
2. 2.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
3. 3.Which of these wastes electricity? (a) switch off empty rooms (b) leave fridge door open (c) set the AC to 24 °C (d) use daylight to read
4. 4.💡 Does it save or waste electricity to unplug idle chargers? (a) saves electricity (b) wastes electricity
5. 5.True or false: to use LED lamps saves electricity. (a) False (b) True
6. 6.🔍 Which is the odd one out? (a) leave the TV on standby (b) leave fridge door open (c) iron one shirt at a time (d) set the AC to 24 °C
7. 7.Which of these saves electricity? (a) use old filament bulbs (b) run fans in empty rooms (c) leave the TV on standby (d) unplug idle chargers
8. 8.🧾 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
9. 9.🔍 Which is the odd one out? (a) leave fridge door open (b) use LED lamps (c) leave the TV on standby (d) run fans in empty rooms
10. 10.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 ampere (c) 1 watt (d) 1 kilowatt-hour (kWh)
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 1 hour. How many watt-hours (Wh) are saved?
12. 12.🧾 A 50 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
13. 13.True or false: to use old filament bulbs wastes electricity. (a) True (b) False
14. 14.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
15. 15.True or false: to iron one shirt at a time saves electricity. (a) False (b) True
16. 16.🧾 A 500 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
17. 17.💡 Does it save or waste electricity to leave fridge door open? (a) wastes electricity (b) saves electricity
18. 18.Which of these saves electricity? (a) switch off empty rooms (b) leave the TV on standby (c) use old filament bulbs (d) run fans in empty rooms
19. 19.🔍 Which is the odd one out? (a) leave the TV on standby (b) unplug idle chargers (c) use old filament bulbs (d) iron one shirt at a time
20. 20.🧾 A 1000 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
21. 21.🧾 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?
22. 22.🔍 Which is the odd one out? (a) run fans in empty rooms (b) iron one shirt at a time (c) use daylight to read (d) leave the TV on standby
23. 23.True or false: to leave fridge door open wastes electricity. (a) True (b) False
24. 24.🧾 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?
25. 25.🧾 A family uses 30 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
26. 26.🧾 A 1000 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
27. 27.🧾 A 500 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
28. 28.🔍 Which is the odd one out? (a) unplug idle chargers (b) close the fridge quickly (c) use daylight to read (d) use old filament bulbs
29. 29.True or false: to unplug idle chargers wastes electricity. (a) True (b) False
30. 30.🧾 A 200 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
31. 31.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
32. 32.True or false: to use LED lamps wastes electricity. (a) False (b) True
33. 33.💡 Does it save or waste electricity to use daylight to read? (a) saves electricity (b) wastes electricity
34. 34.🔍 Which is the odd one out? (a) switch off empty rooms (b) unplug idle chargers (c) run fans in empty rooms (d) use LED lamps
35. 35.🧾 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?
36. 36.🔍 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
37. 37.🧾 A 100 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
38. 38.True or false: to leave the TV on standby wastes electricity. (a) False (b) True
39. 39.💡 Does it save or waste electricity to run fans in empty rooms? (a) saves electricity (b) wastes electricity
40. 40.🧾 A family uses 190 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?

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