Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 770 · 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 use old filament bulbs wastes electricity. (a) True (b) False
2. 2.True or false: to switch off empty rooms saves electricity. (a) False (b) True
3. 3.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 kilowatt-hour (kWh) (c) 1 watt (d) 1 volt
4. 4.Which of these wastes electricity? (a) use daylight to read (b) switch off empty rooms (c) leave the TV on standby (d) unplug idle chargers
5. 5.🧾 A 50 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
6. 6.🔍 Which is the odd one out? (a) set the AC to 24 °C (b) iron one shirt at a time (c) use daylight to read (d) use LED lamps
7. 7.🧾 A family uses 30 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
8. 8.💡 Does it save or waste electricity to use LED lamps? (a) saves electricity (b) wastes electricity
9. 9.True or false: to leave fridge door open wastes electricity. (a) False (b) True
10. 10.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
11. 11.🔍 Which is the odd one out? (a) use LED lamps (b) leave the TV on standby (c) use old filament bulbs (d) run fans in empty rooms
12. 12.True or false: to use daylight to read saves electricity. (a) False (b) True
13. 13.🔍 Which is the odd one out? (a) unplug idle chargers (b) leave the TV on standby (c) iron one shirt at a time (d) run fans in empty rooms
14. 14.Which of these saves electricity? (a) iron one shirt at a time (b) unplug idle chargers (c) use old filament bulbs (d) leave the TV on standby
15. 15.🧾 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?
16. 16.🧾 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?
17. 17.💡 Does it save or waste electricity to run fans in empty rooms? (a) wastes electricity (b) saves electricity
18. 18.💡 Does it save or waste electricity to leave the TV on standby? (a) saves electricity (b) wastes electricity
19. 19.🧾 A 250 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
20. 20.🧾 A family uses 50 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
21. 21.True or false: to leave fridge door open saves electricity. (a) True (b) False
22. 22.True or false: to close the fridge quickly saves electricity. (a) True (b) False
23. 23.Which of these saves electricity? (a) leave fridge door open (b) leave the TV on standby (c) switch off empty rooms (d) run fans in empty rooms
24. 24.Which of these wastes electricity? (a) use daylight to read (b) unplug idle chargers (c) leave fridge door open (d) set the AC to 24 °C
25. 25.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 8 hours. How many watt-hours (Wh) are saved?
26. 26.🧾 Which lamp gives the same light for the least power? (a) an LED lamp (b) an oil lamp (c) a filament bulb (d) a candle
27. 27.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
28. 28.🧾 A family uses 20 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
29. 29.🧾 A 500 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
30. 30.True or false: to leave the TV on standby saves electricity. (a) True (b) False
31. 31.Which of these saves electricity? (a) leave fridge door open (b) use LED lamps (c) leave the TV on standby (d) run fans in empty rooms
32. 32.🔍 Which is the odd one out? (a) switch off empty rooms (b) leave fridge door open (c) use old filament bulbs (d) leave the TV on standby
33. 33.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
34. 34.Which of these wastes electricity? (a) close the fridge quickly (b) set the AC to 24 °C (c) use LED lamps (d) use old filament bulbs
35. 35.🧾 A family uses 140 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
36. 36.💡 Does it save or waste electricity to close the fridge quickly? (a) saves electricity (b) wastes electricity
37. 37.Which of these saves electricity? (a) use daylight to read (b) run fans in empty rooms (c) use old filament bulbs (d) leave the TV on standby
38. 38.🔍 Which is the odd one out? (a) unplug idle chargers (b) leave the TV on standby (c) use LED lamps (d) use daylight to read
39. 39.🧾 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?
40. 40.🧾 A 1500 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =

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