Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 47 · 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.Which of these wastes electricity? (a) leave fridge door open (b) unplug idle chargers (c) use LED lamps (d) use daylight to read
2. 2.🧾 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?
3. 3.True or false: to use old filament bulbs saves electricity. (a) False (b) True
4. 4.🧾 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?
5. 5.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 kilowatt-hour (kWh) (c) 1 ampere (d) 1 volt
6. 6.🧾 A 1000 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
7. 7.🧾 A family uses 20 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
8. 8.🧾 A family uses 130 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
9. 9.🧾 Which lamp gives the same light for the least power? (a) a candle (b) a filament bulb (c) an oil lamp (d) an LED lamp
10. 10.Which of these saves electricity? (a) leave the TV on standby (b) leave fridge door open (c) iron one shirt at a time (d) switch off empty rooms
11. 11.Which of these wastes electricity? (a) switch off empty rooms (b) iron one shirt at a time (c) use daylight to read (d) set the AC to 24 °C
12. 12.🧾 A 200 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
13. 13.🧾 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?
14. 14.🔍 Which is the odd one out? (a) leave fridge door open (b) leave the TV on standby (c) switch off empty rooms (d) run fans in empty rooms
15. 15.🧾 A 50 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
16. 16.Which of these saves electricity? (a) use daylight to read (b) iron one shirt at a time (c) leave fridge door open (d) leave the TV on standby
17. 17.💡 Does it save or waste electricity to use LED lamps? (a) saves electricity (b) wastes electricity
18. 18.🧾 A family uses 90 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
19. 19.🔍 Which is the odd one out? (a) leave fridge door open (b) use old filament bulbs (c) use daylight to read (d) iron one shirt at a time
20. 20.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
21. 21.🧾 A family uses 30 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
22. 22.True or false: to close the fridge quickly saves electricity. (a) True (b) False
23. 23.🔍 Which is the odd one out? (a) close the fridge quickly (b) unplug idle chargers (c) leave fridge door open (d) set the AC to 24 °C
24. 24.💡 Does it save or waste electricity to leave fridge door open? (a) wastes electricity (b) saves electricity
25. 25.True or false: to switch off empty rooms wastes electricity. (a) False (b) True
26. 26.Which of these wastes electricity? (a) use LED lamps (b) use old filament bulbs (c) unplug idle chargers (d) close the fridge quickly
27. 27.True or false: to leave fridge door open saves electricity. (a) False (b) True
28. 28.🧾 A family uses 140 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
29. 29.True or false: to set the AC to 24 °C wastes electricity. (a) True (b) False
30. 30.🧾 A family uses 160 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
31. 31.True or false: to use daylight to read saves electricity. (a) False (b) True
32. 32.🧾 A family uses 90 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
33. 33.🔍 Which is the odd one out? (a) set the AC to 24 °C (b) use LED lamps (c) use daylight to read (d) use old filament bulbs
34. 34.🧾 A family uses 160 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
35. 35.True or false: to close the fridge quickly wastes electricity. (a) True (b) False
36. 36.🔍 Which is the odd one out? (a) iron one shirt at a time (b) set the AC to 24 °C (c) use LED lamps (d) close the fridge quickly
37. 37.💡 Does it save or waste electricity to switch off empty rooms? (a) saves electricity (b) wastes electricity
38. 38.Which of these wastes electricity? (a) switch off empty rooms (b) set the AC to 24 °C (c) unplug idle chargers (d) run fans in empty rooms
39. 39.Which of these wastes electricity? (a) switch off empty rooms (b) use LED lamps (c) leave the TV on standby (d) use daylight to read
40. 40.True or false: to use daylight to read wastes electricity. (a) True (b) False

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