Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 79 · 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.True or false: to unplug idle chargers wastes electricity. (a) True (b) False
2. 2.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
3. 3.🧾 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?
4. 4.💡 Does it save or waste electricity to unplug idle chargers? (a) saves electricity (b) wastes electricity
5. 5.🔍 Which is the odd one out? (a) leave the TV on standby (b) use old filament bulbs (c) run fans in empty rooms (d) set the AC to 24 °C
6. 6.💡 Does it save or waste electricity to use LED lamps? (a) saves electricity (b) wastes electricity
7. 7.💡 Does it save or waste electricity to iron one shirt at a time? (a) saves electricity (b) wastes electricity
8. 8.🧾 A family uses 60 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
9. 9.🧾 A family uses 40 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
10. 10.True or false: to leave the TV on standby wastes electricity. (a) True (b) False
11. 11.🔍 Which is the odd one out? (a) leave the TV on standby (b) close the fridge quickly (c) use old filament bulbs (d) leave fridge door open
12. 12.💡 Does it save or waste electricity to leave the TV on standby? (a) saves electricity (b) wastes electricity
13. 13.🧾 Which lamp gives the same light for the least power? (a) an LED lamp (b) a filament bulb (c) a candle (d) an oil lamp
14. 14.True or false: to iron one shirt at a time wastes electricity. (a) False (b) True
15. 15.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 kilowatt-hour (kWh) (c) 1 ampere (d) 1 watt
16. 16.🔍 Which is the odd one out? (a) leave fridge door open (b) unplug idle chargers (c) use old filament bulbs (d) run fans in empty rooms
17. 17.🧾 A family uses 160 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
18. 18.🧾 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?
19. 19.🧾 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?
20. 20.True or false: to switch off empty rooms wastes electricity. (a) True (b) False
21. 21.💡 Does it save or waste electricity to leave fridge door open? (a) saves electricity (b) wastes electricity
22. 22.True or false: to use LED lamps wastes electricity. (a) True (b) False
23. 23.True or false: to iron one shirt at a time saves electricity. (a) True (b) False
24. 24.Which of these wastes electricity? (a) run fans in empty rooms (b) unplug idle chargers (c) set the AC to 24 °C (d) use LED lamps
25. 25.🧾 A 100 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
26. 26.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 2 hours. How many watt-hours (Wh) are saved?
27. 27.Which of these saves electricity? (a) iron one shirt at a time (b) unplug idle chargers (c) leave fridge door open (d) use old filament bulbs
28. 28.🔍 Which is the odd one out? (a) leave fridge door open (b) use LED lamps (c) run fans in empty rooms (d) leave the TV on standby
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 3 hours. How many watt-hours (Wh) are saved?
30. 30.Which of these saves electricity? (a) switch off empty rooms (b) use old filament bulbs (c) run fans in empty rooms (d) leave the TV on standby
31. 31.Which of these wastes electricity? (a) unplug idle chargers (b) use daylight to read (c) iron one shirt at a time (d) switch off empty rooms
32. 32.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
33. 33.🔍 Which is the odd one out? (a) close the fridge quickly (b) iron one shirt at a time (c) use LED lamps (d) switch off empty rooms
34. 34.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
35. 35.Which of these saves electricity? (a) use LED lamps (b) use old filament bulbs (c) leave fridge door open (d) run fans in empty rooms
36. 36.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 7 hours. How many watt-hours (Wh) are saved?
37. 37.Which of these saves electricity? (a) use daylight to read (b) leave fridge door open (c) run fans in empty rooms (d) use old filament bulbs
38. 38.🧾 A family uses 30 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
39. 39.🧾 A 100 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
40. 40.Which of these saves electricity? (a) use old filament bulbs (b) leave the TV on standby (c) set the AC to 24 °C (d) iron one shirt at a time

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