Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 843 · 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 close the fridge quickly wastes electricity. (a) True (b) False
2. 2.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
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 10 hours. How many watt-hours (Wh) are saved?
4. 4.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 6 hours. How many watt-hours (Wh) are saved?
5. 5.🔍 Which is the odd one out? (a) leave fridge door open (b) iron one shirt at a time (c) unplug idle chargers (d) use old filament bulbs
6. 6.🧾 A family uses 90 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
7. 7.💡 Does it save or waste electricity to leave fridge door open? (a) saves electricity (b) wastes electricity
8. 8.🧾 A 50 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
9. 9.🧾 A 2000 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
10. 10.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 volt (c) 1 ampere (d) 1 kilowatt-hour (kWh)
11. 11.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) a candle (c) an LED lamp (d) a filament bulb
12. 12.🔍 Which is the odd one out? (a) run fans in empty rooms (b) set the AC to 24 °C (c) leave the TV on standby (d) iron one shirt at a time
13. 13.True or false: to unplug idle chargers saves electricity. (a) True (b) False
14. 14.🔍 Which is the odd one out? (a) close the fridge quickly (b) run fans in empty rooms (c) set the AC to 24 °C (d) unplug idle chargers
15. 15.🧾 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?
16. 16.🔍 Which is the odd one out? (a) use daylight to read (b) use LED lamps (c) close the fridge quickly (d) leave fridge door open
17. 17.🧾 A 100 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
18. 18.💡 Does it save or waste electricity to leave the TV on standby? (a) saves electricity (b) wastes electricity
19. 19.🧾 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?
20. 20.💡 Does it save or waste electricity to iron one shirt at a time? (a) saves electricity (b) wastes electricity
21. 21.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
22. 22.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
23. 23.True or false: to leave fridge door open wastes electricity. (a) False (b) True
24. 24.🧾 A 1000 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
25. 25.🔍 Which is the odd one out? (a) use old filament bulbs (b) iron one shirt at a time (c) use LED lamps (d) leave the TV on standby
26. 26.💡 Does it save or waste electricity to unplug idle chargers? (a) saves electricity (b) wastes electricity
27. 27.🧾 A 500 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
28. 28.Which of these wastes electricity? (a) use old filament bulbs (b) use LED lamps (c) switch off empty rooms (d) use daylight to read
29. 29.True or false: to use LED lamps wastes electricity. (a) True (b) False
30. 30.💡 Does it save or waste electricity to switch off empty rooms? (a) saves electricity (b) wastes electricity
31. 31.🧾 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?
32. 32.🧾 A family uses 60 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
33. 33.Which of these wastes electricity? (a) leave the TV on standby (b) unplug idle chargers (c) use LED lamps (d) switch off empty rooms
34. 34.🧾 A 1500 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
35. 35.🔍 Which is the odd one out? (a) unplug idle chargers (b) use daylight to read (c) use LED lamps (d) iron one shirt at a time
36. 36.🧾 A 1500 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
37. 37.🔍 Which is the odd one out? (a) use old filament bulbs (b) use LED lamps (c) unplug idle chargers (d) switch off empty rooms
38. 38.💡 Does it save or waste electricity to run fans in empty rooms? (a) wastes electricity (b) saves electricity
39. 39.🧾 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?
40. 40.🧾 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?

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