Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 258 · 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.🔍 Which is the odd one out? (a) run fans in empty rooms (b) unplug idle chargers (c) use LED lamps (d) close the fridge quickly
3. 3.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
4. 4.💡 Does it save or waste electricity to use old filament bulbs? (a) saves electricity (b) wastes electricity
5. 5.Which of these saves electricity? (a) leave fridge door open (b) run fans in empty rooms (c) iron one shirt at a time (d) set the AC to 24 °C
6. 6.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
7. 7.True or false: to use daylight to read saves electricity. (a) False (b) True
8. 8.🧾 A 50 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
9. 9.Which of these saves electricity? (a) leave fridge door open (b) unplug idle chargers (c) leave the TV on standby (d) run fans in empty rooms
10. 10.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
11. 11.💡 Does it save or waste electricity to use LED lamps? (a) saves electricity (b) wastes electricity
12. 12.True or false: to set the AC to 24 °C saves electricity. (a) False (b) True
13. 13.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) an LED lamp (c) a candle (d) an oil lamp
14. 14.True or false: to iron one shirt at a time wastes electricity. (a) True (b) False
15. 15.🔍 Which is the odd one out? (a) close the fridge quickly (b) switch off empty rooms (c) set the AC to 24 °C (d) leave fridge door open
16. 16.True or false: to unplug idle chargers wastes electricity. (a) False (b) True
17. 17.🧾 A 1000 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
18. 18.🔍 Which is the odd one out? (a) use LED lamps (b) unplug idle chargers (c) switch off empty rooms (d) iron one shirt at a time
19. 19.🧾 A 500 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
20. 20.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 ampere (c) 1 kilowatt-hour (kWh) (d) 1 volt
21. 21.💡 Does it save or waste electricity to leave fridge door open? (a) wastes electricity (b) saves electricity
22. 22.Which of these saves electricity? (a) use daylight to read (b) iron one shirt at a time (c) use old filament bulbs (d) run fans in empty rooms
23. 23.🔍 Which is the odd one out? (a) run fans in empty rooms (b) use old filament bulbs (c) iron one shirt at a time (d) use daylight to read
24. 24.🔍 Which is the odd one out? (a) close the fridge quickly (b) leave the TV on standby (c) set the AC to 24 °C (d) use daylight to read
25. 25.🧾 A family uses 40 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
26. 26.🧾 A 200 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
27. 27.True or false: to use LED lamps saves electricity. (a) True (b) False
28. 28.🧾 A family uses 30 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
29. 29.True or false: to switch off empty rooms saves electricity. (a) True (b) False
30. 30.Which of these wastes electricity? (a) use LED lamps (b) switch off empty rooms (c) leave fridge door open (d) unplug idle chargers
31. 31.🧾 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?
32. 32.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 5 hours. How many watt-hours (Wh) are saved?
33. 33.🧾 A 2000 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
34. 34.💡 Does it save or waste electricity to run fans in empty rooms? (a) wastes electricity (b) saves electricity
35. 35.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 7 hours. How many watt-hours (Wh) are saved?
36. 36.🧾 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?
37. 37.🧾 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?
38. 38.🧾 A family uses 60 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
39. 39.🧾 A 50 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
40. 40.🔍 Which is the odd one out? (a) leave the TV on standby (b) run fans in empty rooms (c) leave fridge door open (d) switch off empty rooms

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