Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 29 · 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 7 hours. How many watt-hours (Wh) are saved?
2. 2.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 8 hours. How many watt-hours (Wh) are saved?
3. 3.🧾 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?
4. 4.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 volt (c) 1 kilowatt-hour (kWh) (d) 1 watt
5. 5.True or false: to use LED lamps saves electricity. (a) False (b) True
6. 6.🧾 A 50 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
7. 7.True or false: to use daylight to read saves electricity. (a) False (b) True
8. 8.Which of these wastes electricity? (a) iron one shirt at a time (b) switch off empty rooms (c) use LED lamps (d) use daylight to read
9. 9.🧾 A 2000 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
10. 10.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
11. 11.🧾 A 200 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
12. 12.Which of these wastes electricity? (a) leave the TV on standby (b) switch off empty rooms (c) unplug idle chargers (d) use LED lamps
13. 13.🧾 A 250 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
14. 14.💡 Does it save or waste electricity to close the fridge quickly? (a) wastes electricity (b) saves electricity
15. 15.True or false: to iron one shirt at a time saves electricity. (a) True (b) False
16. 16.💡 Does it save or waste electricity to use old filament bulbs? (a) saves electricity (b) wastes electricity
17. 17.True or false: to iron one shirt at a time wastes electricity. (a) False (b) True
18. 18.🧾 A family uses 120 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
19. 19.🔍 Which is the odd one out? (a) leave fridge door open (b) leave the TV on standby (c) use old filament bulbs (d) unplug idle chargers
20. 20.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) a candle (c) a filament bulb (d) an LED lamp
21. 21.🔍 Which is the odd one out? (a) use old filament bulbs (b) use LED lamps (c) close the fridge quickly (d) switch off empty rooms
22. 22.🧾 A 50 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
23. 23.💡 Does it save or waste electricity to run fans in empty rooms? (a) saves electricity (b) wastes electricity
24. 24.🧾 A 1500 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
25. 25.True or false: to close the fridge quickly saves electricity. (a) True (b) False
26. 26.🧾 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?
27. 27.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 6 hours. How many watt-hours (Wh) are saved?
28. 28.Which of these saves electricity? (a) unplug idle chargers (b) leave fridge door open (c) use old filament bulbs (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 2 hours. How many watt-hours (Wh) are saved?
30. 30.True or false: to unplug idle chargers wastes electricity. (a) False (b) True
31. 31.True or false: to leave fridge door open saves electricity. (a) True (b) False
32. 32.Which of these wastes electricity? (a) use daylight to read (b) set the AC to 24 °C (c) close the fridge quickly (d) leave fridge door open
33. 33.True or false: to run fans in empty rooms wastes electricity. (a) False (b) True
34. 34.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 3 hours. How many watt-hours (Wh) are saved?
35. 35.🧾 A 100 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
36. 36.🔍 Which is the odd one out? (a) unplug idle chargers (b) use daylight to read (c) leave fridge door open (d) switch off empty rooms
37. 37.🔍 Which is the odd one out? (a) iron one shirt at a time (b) leave fridge door open (c) run fans in empty rooms (d) switch off empty rooms
38. 38.🧾 A family uses 20 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
39. 39.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
40. 40.🧾 A family uses 90 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?

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