Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 233 · 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 1 hour. How many watt-hours (Wh) are saved?
2. 2.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
3. 3.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
4. 4.True or false: to switch off empty rooms saves electricity. (a) True (b) False
5. 5.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) an oil lamp (c) a candle (d) an LED lamp
6. 6.True or false: to leave the TV on standby wastes electricity. (a) False (b) True
7. 7.🧾 A family uses 170 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
8. 8.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 volt (c) 1 kilowatt-hour (kWh) (d) 1 watt
9. 9.True or false: to use daylight to read wastes electricity. (a) False (b) True
10. 10.True or false: to close the fridge quickly saves electricity. (a) True (b) False
11. 11.Which of these saves electricity? (a) iron one shirt at a time (b) leave fridge door open (c) use old filament bulbs (d) use LED lamps
12. 12.🧾 A 50 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
13. 13.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
14. 14.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 5 hours. How many watt-hours (Wh) are saved?
15. 15.True or false: to leave the TV on standby saves electricity. (a) True (b) False
16. 16.Which of these wastes electricity? (a) use daylight to read (b) use old filament bulbs (c) use LED lamps (d) switch off empty rooms
17. 17.True or false: to unplug idle chargers wastes electricity. (a) False (b) True
18. 18.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
19. 19.True or false: to unplug idle chargers saves electricity. (a) False (b) True
20. 20.🧾 A 250 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
21. 21.Which of these wastes electricity? (a) switch off empty rooms (b) unplug idle chargers (c) leave the TV on standby (d) close the fridge quickly
22. 22.🧾 A 1500 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
23. 23.🔍 Which is the odd one out? (a) unplug idle chargers (b) switch off empty rooms (c) use LED lamps (d) leave the TV on standby
24. 24.True or false: to use daylight to read saves electricity. (a) False (b) True
25. 25.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
26. 26.True or false: to use old filament bulbs wastes electricity. (a) True (b) False
27. 27.🧾 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?
28. 28.Which of these wastes electricity? (a) unplug idle chargers (b) switch off empty rooms (c) use LED lamps (d) iron one shirt at a time
29. 29.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 1 hour. How many watt-hours (Wh) are saved?
30. 30.🧾 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?
31. 31.Which of these wastes electricity? (a) leave fridge door open (b) close the fridge quickly (c) set the AC to 24 °C (d) use LED lamps
32. 32.🧾 A family uses 60 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
33. 33.🧾 A 250 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
34. 34.🔍 Which is the odd one out? (a) use old filament bulbs (b) run fans in empty rooms (c) leave the TV on standby (d) switch off empty rooms
35. 35.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
36. 36.🧾 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?
37. 37.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
38. 38.True or false: to leave fridge door open saves electricity. (a) False (b) True
39. 39.🧾 A family uses 140 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
40. 40.🧾 A family uses 40 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?

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