Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 7 · 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 LED lamps wastes electricity. (a) True (b) False
2. 2.Which of these wastes electricity? (a) use daylight to read (b) use LED lamps (c) unplug idle chargers (d) run fans in empty rooms
3. 3.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 volt (c) 1 ampere (d) 1 kilowatt-hour (kWh)
4. 4.🔍 Which is the odd one out? (a) switch off empty rooms (b) set the AC to 24 °C (c) leave fridge door open (d) unplug idle chargers
5. 5.🧾 A family uses 30 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
6. 6.💡 Does it save or waste electricity to run fans in empty rooms? (a) wastes electricity (b) saves electricity
7. 7.🧾 A family uses 200 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
8. 8.Which of these wastes electricity? (a) switch off empty rooms (b) unplug idle chargers (c) close the fridge quickly (d) use old filament bulbs
9. 9.💡 Does it save or waste electricity to leave the TV on standby? (a) saves electricity (b) wastes electricity
10. 10.Which of these saves electricity? (a) use LED lamps (b) leave the TV on standby (c) iron one shirt at a time (d) leave fridge door open
11. 11.🧾 A family uses 20 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
12. 12.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
13. 13.🧾 Which lamp gives the same light for the least power? (a) an LED lamp (b) a candle (c) an oil lamp (d) a filament bulb
14. 14.Which of these saves electricity? (a) leave fridge door open (b) iron one shirt at a time (c) use old filament bulbs (d) use daylight to read
15. 15.🧾 A 1500 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
16. 16.🧾 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?
17. 17.Which of these saves electricity? (a) leave the TV on standby (b) close the fridge quickly (c) leave fridge door open (d) iron one shirt at a time
18. 18.True or false: to leave the TV on standby saves electricity. (a) False (b) True
19. 19.True or false: to set the AC to 24 °C saves electricity. (a) False (b) True
20. 20.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
21. 21.🧾 A 50 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
22. 22.True or false: to unplug idle chargers wastes electricity. (a) True (b) False
23. 23.🔍 Which is the odd one out? (a) iron one shirt at a time (b) leave the TV on standby (c) leave fridge door open (d) set the AC to 24 °C
24. 24.Which of these saves electricity? (a) leave fridge door open (b) iron one shirt at a time (c) use old filament bulbs (d) set the AC to 24 °C
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 7 hours. How many watt-hours (Wh) are saved?
26. 26.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
27. 27.Which of these wastes electricity? (a) use daylight to read (b) set the AC to 24 °C (c) leave fridge door open (d) use LED lamps
28. 28.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
29. 29.🔍 Which is the odd one out? (a) leave fridge door open (b) use daylight to read (c) iron one shirt at a time (d) run fans in empty rooms
30. 30.🔍 Which is the odd one out? (a) leave the TV on standby (b) switch off empty rooms (c) run fans in empty rooms (d) leave fridge door open
31. 31.💡 Does it save or waste electricity to close the fridge quickly? (a) saves electricity (b) wastes electricity
32. 32.🧾 A 1500 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
33. 33.🧾 A 50 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
34. 34.🧾 A 1000 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
35. 35.💡 Does it save or waste electricity to use old filament bulbs? (a) saves electricity (b) wastes electricity
36. 36.Which of these saves electricity? (a) leave the TV on standby (b) use old filament bulbs (c) leave fridge door open (d) unplug idle chargers
37. 37.🔍 Which is the odd one out? (a) run fans in empty rooms (b) switch off empty rooms (c) set the AC to 24 °C (d) unplug idle chargers
38. 38.🧾 A 200 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
39. 39.🔍 Which is the odd one out? (a) use old filament bulbs (b) switch off empty rooms (c) set the AC to 24 °C (d) unplug idle chargers
40. 40.True or false: to use LED lamps saves electricity. (a) False (b) True

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