Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 12 · 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 10 hours. How many watt-hours (Wh) are saved?
2. 2.🧾 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?
3. 3.True or false: to close the fridge quickly saves electricity. (a) False (b) True
4. 4.🔍 Which is the odd one out? (a) use daylight to read (b) set the AC to 24 °C (c) run fans in empty rooms (d) use LED lamps
5. 5.Which of these saves electricity? (a) iron one shirt at a time (b) leave fridge door open (c) switch off empty rooms (d) run fans in empty rooms
6. 6.🔍 Which is the odd one out? (a) use old filament bulbs (b) run fans in empty rooms (c) switch off empty rooms (d) leave fridge door open
7. 7.🔍 Which is the odd one out? (a) iron one shirt at a time (b) use old filament bulbs (c) run fans in empty rooms (d) set the AC to 24 °C
8. 8.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) an oil lamp (c) an LED lamp (d) a candle
9. 9.💡 Does it save or waste electricity to close the fridge quickly? (a) wastes electricity (b) saves electricity
10. 10.🧾 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?
11. 11.🧾 A 500 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
12. 12.True or false: to set the AC to 24 °C saves electricity. (a) False (b) True
13. 13.True or false: to use old filament bulbs wastes electricity. (a) True (b) False
14. 14.💡 Does it save or waste electricity to run fans in empty rooms? (a) wastes electricity (b) saves electricity
15. 15.🧾 A 500 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
16. 16.Which of these wastes electricity? (a) use LED lamps (b) run fans in empty rooms (c) use daylight to read (d) close the fridge quickly
17. 17.True or false: to use daylight to read wastes electricity. (a) True (b) False
18. 18.Which of these saves electricity? (a) leave the TV on standby (b) use old filament bulbs (c) run fans in empty rooms (d) use LED lamps
19. 19.Which of these saves electricity? (a) use daylight to read (b) iron one shirt at a time (c) use old filament bulbs (d) leave the TV on standby
20. 20.🧾 A 1500 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
21. 21.🧾 A family uses 150 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
22. 22.🧾 A 500 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
23. 23.Which of these wastes electricity? (a) switch off empty rooms (b) use daylight to read (c) use LED lamps (d) use old filament bulbs
24. 24.🔍 Which is the odd one out? (a) leave the TV on standby (b) use daylight to read (c) use old filament bulbs (d) run fans in empty rooms
25. 25.🧾 A 250 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
26. 26.🧾 One “unit” on an electricity bill is … (a) 1 kilowatt-hour (kWh) (b) 1 volt (c) 1 watt (d) 1 ampere
27. 27.💡 Does it save or waste electricity to unplug idle chargers? (a) saves electricity (b) wastes electricity
28. 28.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
29. 29.🔍 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
30. 30.🧾 A 1500 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
31. 31.Which of these wastes electricity? (a) iron one shirt at a time (b) use daylight to read (c) use LED lamps (d) close the fridge quickly
32. 32.🔍 Which is the odd one out? (a) switch off empty rooms (b) close the fridge quickly (c) set the AC to 24 °C (d) leave the TV on standby
33. 33.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
34. 34.💡 Does it save or waste electricity to switch off empty rooms? (a) saves electricity (b) wastes electricity
35. 35.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
36. 36.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
37. 37.🧾 A family uses 120 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
38. 38.🧾 A family uses 190 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
39. 39.True or false: to switch off empty rooms saves electricity. (a) True (b) False
40. 40.🧾 A family uses 170 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?

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