Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 455 · 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 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 10 hours. How many watt-hours (Wh) are saved?
2. 2.True or false: to use LED lamps saves electricity. (a) False (b) True
3. 3.💡 Does it save or waste electricity to leave fridge door open? (a) wastes electricity (b) saves electricity
4. 4.Which of these wastes electricity? (a) use daylight to read (b) use old filament bulbs (c) use LED lamps (d) close the fridge quickly
5. 5.Which of these saves electricity? (a) leave the TV on standby (b) switch off empty rooms (c) leave fridge door open (d) use old filament bulbs
6. 6.🧾 A 100 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
7. 7.🧾 A family uses 160 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
8. 8.True or false: to leave the TV on standby wastes electricity. (a) True (b) False
9. 9.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 ampere (c) 1 watt (d) 1 kilowatt-hour (kWh)
10. 10.Which of these saves electricity? (a) use old filament bulbs (b) close the fridge quickly (c) leave fridge door open (d) run fans in empty rooms
11. 11.🔍 Which is the odd one out? (a) leave fridge door open (b) use old filament bulbs (c) close the fridge quickly (d) leave the TV on standby
12. 12.Which of these wastes electricity? (a) switch off empty rooms (b) leave the TV on standby (c) use LED lamps (d) close the fridge quickly
13. 13.🧾 A 1000 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
14. 14.True or false: to unplug idle chargers wastes electricity. (a) True (b) False
15. 15.🧾 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
16. 16.💡 Does it save or waste electricity to unplug idle chargers? (a) saves electricity (b) wastes electricity
17. 17.Which of these saves electricity? (a) iron one shirt at a time (b) run fans in empty rooms (c) leave the TV on standby (d) use LED lamps
18. 18.Which of these wastes electricity? (a) set the AC to 24 °C (b) iron one shirt at a time (c) close the fridge quickly (d) use daylight to read
19. 19.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 2 hours. How many watt-hours (Wh) are saved?
20. 20.Which of these wastes electricity? (a) use LED lamps (b) run fans in empty rooms (c) switch off empty rooms (d) unplug idle chargers
21. 21.🧾 A family uses 200 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
22. 22.🔍 Which is the odd one out? (a) use daylight to read (b) switch off empty rooms (c) use old filament bulbs (d) close the fridge quickly
23. 23.True or false: to unplug idle chargers saves electricity. (a) False (b) True
24. 24.🔍 Which is the odd one out? (a) switch off empty rooms (b) close the fridge quickly (c) unplug idle chargers (d) iron one shirt at a time
25. 25.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 8 hours. How many watt-hours (Wh) are saved?
26. 26.True or false: to switch off empty rooms saves electricity. (a) False (b) True
27. 27.🔍 Which is the odd one out? (a) leave fridge door open (b) iron one shirt at a time (c) unplug idle chargers (d) use old filament bulbs
28. 28.True or false: to close the fridge quickly saves electricity. (a) False (b) True
29. 29.💡 Does it save or waste electricity to use old filament bulbs? (a) saves electricity (b) wastes electricity
30. 30.True or false: to use daylight to read saves electricity. (a) False (b) True
31. 31.🧾 A 1500 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
32. 32.Which of these wastes electricity? (a) set the AC to 24 °C (b) close the fridge quickly (c) leave fridge door open (d) use daylight to read
33. 33.🧾 A 50 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
34. 34.🔍 Which is the odd one out? (a) run fans in empty rooms (b) iron one shirt at a time (c) leave fridge door open (d) use LED lamps
35. 35.💡 Does it save or waste electricity to use LED lamps? (a) saves electricity (b) wastes electricity
36. 36.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
37. 37.🧾 A family uses 140 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
38. 38.🧾 A family uses 150 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
39. 39.True or false: to use LED lamps wastes electricity. (a) True (b) False
40. 40.🧾 A 50 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =

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