Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 876 · 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.💡 Does it save or waste electricity to unplug idle chargers? (a) wastes electricity (b) saves electricity
2. 2.💡 Does it save or waste electricity to close the fridge quickly? (a) saves electricity (b) wastes electricity
3. 3.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 10 hours. How many watt-hours (Wh) are saved?
4. 4.💡 Does it save or waste electricity to leave the TV on standby? (a) saves electricity (b) wastes electricity
5. 5.🔍 Which is the odd one out? (a) leave fridge door open (b) leave the TV on standby (c) run fans in empty rooms (d) set the AC to 24 °C
6. 6.Which of these saves electricity? (a) leave the TV on standby (b) use daylight to read (c) leave fridge door open (d) use old filament bulbs
7. 7.Which of these saves electricity? (a) switch off empty rooms (b) leave fridge door open (c) use old filament bulbs (d) run fans in empty rooms
8. 8.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
9. 9.🔍 Which is the odd one out? (a) use daylight to read (b) leave the TV on standby (c) use LED lamps (d) close the fridge quickly
10. 10.🔍 Which is the odd one out? (a) leave the TV on standby (b) leave fridge door open (c) run fans in empty rooms (d) use daylight to read
11. 11.🧾 A family uses 30 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
12. 12.💡 Does it save or waste electricity to switch off empty rooms? (a) saves electricity (b) wastes electricity
13. 13.💡 Does it save or waste electricity to leave fridge door open? (a) saves electricity (b) wastes electricity
14. 14.True or false: to leave fridge door open wastes electricity. (a) True (b) False
15. 15.💡 Does it save or waste electricity to run fans in empty rooms? (a) wastes electricity (b) saves electricity
16. 16.True or false: to leave the TV on standby saves electricity. (a) False (b) True
17. 17.🧾 A family uses 130 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
18. 18.🧾 A 100 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
19. 19.🧾 One “unit” on an electricity bill is … (a) 1 kilowatt-hour (kWh) (b) 1 ampere (c) 1 volt (d) 1 watt
20. 20.Which of these wastes electricity? (a) iron one shirt at a time (b) use LED lamps (c) switch off empty rooms (d) use daylight to read
21. 21.🧾 A family uses 160 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
22. 22.🧾 A family uses 100 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
23. 23.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
24. 24.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 8 hours. How many watt-hours (Wh) are saved?
25. 25.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
26. 26.🧾 A 100 W filament bulb is swapped for a 15 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 is the odd one out? (a) set the AC to 24 °C (b) unplug idle chargers (c) close the fridge quickly (d) iron one shirt at a time
28. 28.🧾 A 1000 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
29. 29.True or false: to set the AC to 24 °C wastes electricity. (a) False (b) True
30. 30.True or false: to use old filament bulbs wastes electricity. (a) False (b) True
31. 31.True or false: to unplug idle chargers wastes electricity. (a) False (b) True
32. 32.🧾 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?
33. 33.True or false: to switch off empty rooms wastes electricity. (a) True (b) False
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 6 hours. How many watt-hours (Wh) are saved?
35. 35.🧾 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?
36. 36.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) a candle (c) an oil lamp (d) an LED lamp
37. 37.🧾 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?
38. 38.🧾 A family uses 150 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
39. 39.🔍 Which is the odd one out? (a) use LED lamps (b) use old filament bulbs (c) set the AC to 24 °C (d) switch off empty rooms
40. 40.True or false: to close the fridge quickly wastes electricity. (a) True (b) False

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