Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 124 · 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 3 hours. How many watt-hours (Wh) are saved?
2. 2.🧾 A family uses 130 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
3. 3.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 8 hours. How many watt-hours (Wh) are saved?
4. 4.🧾 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
5. 5.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 kilowatt-hour (kWh) (c) 1 ampere (d) 1 watt
6. 6.🔍 Which is the odd one out? (a) close the fridge quickly (b) use old filament bulbs (c) set the AC to 24 °C (d) use daylight to read
7. 7.🧾 A 250 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
8. 8.🔍 Which is the odd one out? (a) close the fridge quickly (b) set the AC to 24 °C (c) run fans in empty rooms (d) unplug idle chargers
9. 9.Which of these wastes electricity? (a) close the fridge quickly (b) set the AC to 24 °C (c) use daylight to read (d) run fans in empty rooms
10. 10.True or false: to close the fridge quickly wastes electricity. (a) False (b) True
11. 11.🔍 Which is the odd one out? (a) use old filament bulbs (b) iron one shirt at a time (c) switch off empty rooms (d) leave the TV on standby
12. 12.💡 Does it save or waste electricity to close the fridge quickly? (a) wastes electricity (b) saves electricity
13. 13.🧾 A family uses 130 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
14. 14.🧾 A family uses 70 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
15. 15.Which of these saves electricity? (a) leave the TV on standby (b) iron one shirt at a time (c) leave fridge door open (d) switch off empty rooms
16. 16.🔍 Which is the odd one out? (a) use old filament bulbs (b) use daylight to read (c) iron one shirt at a time (d) leave the TV on standby
17. 17.Which of these wastes electricity? (a) set the AC to 24 °C (b) use daylight to read (c) unplug idle chargers (d) leave the TV on standby
18. 18.True or false: to run fans in empty rooms saves electricity. (a) False (b) True
19. 19.💡 Does it save or waste electricity to use old filament bulbs? (a) saves electricity (b) wastes electricity
20. 20.Which of these wastes electricity? (a) switch off empty rooms (b) leave fridge door open (c) close the fridge quickly (d) set the AC to 24 °C
21. 21.🧾 A 1000 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
22. 22.🧾 A family uses 60 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
23. 23.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 1 hour. How many watt-hours (Wh) are saved?
24. 24.🧾 A family uses 60 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
25. 25.🧾 A family uses 190 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
26. 26.True or false: to switch off empty rooms wastes electricity. (a) True (b) False
27. 27.Which of these saves electricity? (a) use daylight to read (b) run fans in empty rooms (c) iron one shirt at a time (d) use old filament bulbs
28. 28.🔍 Which is the odd one out? (a) switch off empty rooms (b) unplug idle chargers (c) leave the TV on standby (d) set the AC to 24 °C
29. 29.💡 Does it save or waste electricity to switch off empty rooms? (a) saves electricity (b) wastes electricity
30. 30.🧾 A family uses 80 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
31. 31.🔍 Which is the odd one out? (a) set the AC to 24 °C (b) close the fridge quickly (c) iron one shirt at a time (d) switch off empty rooms
32. 32.Which of these saves electricity? (a) leave fridge door open (b) unplug idle chargers (c) run fans in empty rooms (d) leave the TV on standby
33. 33.🧾 A 1500 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
34. 34.🧾 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?
35. 35.🧾 A 2000 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
36. 36.True or false: to run fans in empty rooms wastes electricity. (a) False (b) True
37. 37.💡 Does it save or waste electricity to run fans in empty rooms? (a) wastes electricity (b) saves electricity
38. 38.True or false: to switch off empty rooms saves electricity. (a) False (b) True
39. 39.💡 Does it save or waste electricity to leave the TV on standby? (a) saves electricity (b) wastes electricity
40. 40.💡 Does it save or waste electricity to iron one shirt at a time? (a) saves electricity (b) wastes electricity

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