Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 506 · 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 leave fridge door open? (a) saves electricity (b) wastes electricity
2. 2.🧾 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?
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.🔍 Which is the odd one out? (a) unplug idle chargers (b) use daylight to read (c) iron one shirt at a time (d) switch off empty rooms
5. 5.True or false: to leave fridge door open saves electricity. (a) False (b) True
6. 6.True or false: to iron one shirt at a time wastes electricity. (a) True (b) False
7. 7.🔍 Which is the odd one out? (a) close the fridge quickly (b) switch off empty rooms (c) use daylight to read (d) use old filament bulbs
8. 8.Which of these saves electricity? (a) iron one shirt at a time (b) leave the TV on standby (c) set the AC to 24 °C (d) run fans in empty rooms
9. 9.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
10. 10.Which of these wastes electricity? (a) iron one shirt at a time (b) close the fridge quickly (c) use LED lamps (d) unplug idle chargers
11. 11.🧾 One “unit” on an electricity bill is … (a) 1 kilowatt-hour (kWh) (b) 1 watt (c) 1 volt (d) 1 ampere
12. 12.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
13. 13.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) a filament bulb (c) a candle (d) an LED lamp
14. 14.🧾 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?
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 1 hour. How many watt-hours (Wh) are saved?
16. 16.🧾 A 50 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
17. 17.True or false: to use old filament bulbs saves electricity. (a) False (b) True
18. 18.🔍 Which is the odd one out? (a) use old filament bulbs (b) run fans in empty rooms (c) iron one shirt at a time (d) unplug idle chargers
19. 19.True or false: to switch off empty rooms wastes electricity. (a) False (b) True
20. 20.Which of these wastes electricity? (a) use daylight to read (b) use LED lamps (c) leave the TV on standby (d) set the AC to 24 °C
21. 21.🧾 A family uses 20 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
22. 22.🧾 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?
23. 23.🔍 Which is the odd one out? (a) run fans in empty rooms (b) set the AC to 24 °C (c) use LED lamps (d) close the fridge quickly
24. 24.Which of these saves electricity? (a) iron one shirt at a time (b) run fans in empty rooms (c) leave fridge door open (d) close the fridge quickly
25. 25.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
26. 26.💡 Does it save or waste electricity to use old filament bulbs? (a) saves electricity (b) wastes electricity
27. 27.Which of these saves electricity? (a) use daylight to read (b) run fans in empty rooms (c) leave fridge door open (d) leave the TV on standby
28. 28.🧾 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?
29. 29.🧾 A family uses 200 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
30. 30.🧾 A 200 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
31. 31.🧾 A 1000 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
32. 32.🧾 A 2000 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
33. 33.True or false: to use old filament bulbs wastes electricity. (a) False (b) True
34. 34.🧾 A family uses 190 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
35. 35.🧾 A family uses 190 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
36. 36.True or false: to use daylight to read wastes electricity. (a) False (b) True
37. 37.🧾 A 250 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
38. 38.🧾 A family uses 40 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
39. 39.💡 Does it save or waste electricity to switch off empty rooms? (a) saves electricity (b) wastes electricity
40. 40.🧾 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?

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