Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 438 · 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 1 hour. How many watt-hours (Wh) are saved?
2. 2.🔍 Which is the odd one out? (a) use old filament bulbs (b) leave fridge door open (c) switch off empty rooms (d) leave the TV on standby
3. 3.🔍 Which is the odd one out? (a) leave the TV on standby (b) close the fridge quickly (c) use LED lamps (d) switch off empty rooms
4. 4.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
5. 5.True or false: to use LED lamps wastes electricity. (a) True (b) False
6. 6.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
7. 7.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 5 hours. How many watt-hours (Wh) are saved?
8. 8.Which of these saves electricity? (a) leave the TV on standby (b) use daylight to read (c) run fans in empty rooms (d) iron one shirt at a time
9. 9.🧾 A 2000 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
10. 10.🔍 Which is the odd one out? (a) use old filament bulbs (b) close the fridge quickly (c) switch off empty rooms (d) use daylight to read
11. 11.🧾 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?
12. 12.🧾 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?
13. 13.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 ampere (c) 1 watt (d) 1 kilowatt-hour (kWh)
14. 14.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
15. 15.Which of these wastes electricity? (a) use LED lamps (b) switch off empty rooms (c) unplug idle chargers (d) run fans in empty rooms
16. 16.Which of these wastes electricity? (a) use LED lamps (b) use daylight to read (c) switch off empty rooms (d) use old filament bulbs
17. 17.Which of these saves electricity? (a) run fans in empty rooms (b) leave fridge door open (c) use old filament bulbs (d) unplug idle chargers
18. 18.True or false: to unplug idle chargers wastes electricity. (a) True (b) False
19. 19.🧾 A family uses 160 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
20. 20.🧾 A family uses 170 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
21. 21.True or false: to iron one shirt at a time saves electricity. (a) False (b) True
22. 22.Which of these saves electricity? (a) leave fridge door open (b) set the AC to 24 °C (c) use old filament bulbs (d) leave the TV on standby
23. 23.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
24. 24.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 3 hours. How many watt-hours (Wh) are saved?
25. 25.True or false: to leave the TV on standby wastes electricity. (a) True (b) False
26. 26.💡 Does it save or waste electricity to leave fridge door open? (a) saves electricity (b) wastes electricity
27. 27.🔍 Which is the odd one out? (a) use LED lamps (b) use old filament bulbs (c) leave the TV on standby (d) iron one shirt at a time
28. 28.🔍 Which is the odd one out? (a) use LED lamps (b) unplug idle chargers (c) leave fridge door open (d) use daylight to read
29. 29.Which of these wastes electricity? (a) set the AC to 24 °C (b) unplug idle chargers (c) leave fridge door open (d) use LED lamps
30. 30.🔍 Which is the odd one out? (a) use daylight to read (b) close the fridge quickly (c) run fans in empty rooms (d) switch off empty rooms
31. 31.🧾 A family uses 150 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
32. 32.🧾 A 50 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
33. 33.Which of these saves electricity? (a) switch off empty rooms (b) leave fridge door open (c) iron one shirt at a time (d) run fans in empty rooms
34. 34.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
35. 35.💡 Does it save or waste electricity to unplug idle chargers? (a) saves electricity (b) wastes electricity
36. 36.🔍 Which is the odd one out? (a) leave the TV on standby (b) leave fridge door open (c) set the AC to 24 °C (d) use old filament bulbs
37. 37.🔍 Which is the odd one out? (a) run fans in empty rooms (b) close the fridge quickly (c) leave the TV on standby (d) leave fridge door open
38. 38.True or false: to unplug idle chargers saves electricity. (a) True (b) False
39. 39.True or false: to use old filament bulbs saves electricity. (a) False (b) True
40. 40.True or false: to close the fridge quickly wastes electricity. (a) False (b) True

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