Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 42 · 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 switch off empty rooms? (a) saves electricity (b) wastes electricity
2. 2.True or false: to set the AC to 24 °C wastes electricity. (a) False (b) True
3. 3.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
4. 4.🔍 Which is the odd one out? (a) leave fridge door open (b) switch off empty rooms (c) leave the TV on standby (d) iron one shirt at a time
5. 5.🧾 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?
6. 6.💡 Does it save or waste electricity to run fans in empty rooms? (a) saves electricity (b) wastes electricity
7. 7.🧾 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?
8. 8.🧾 A 2000 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
9. 9.🔍 Which is the odd one out? (a) close the fridge quickly (b) set the AC to 24 °C (c) run fans in empty rooms (d) use daylight to read
10. 10.💡 Does it save or waste electricity to leave the TV on standby? (a) saves electricity (b) wastes electricity
11. 11.Which of these wastes electricity? (a) switch off empty rooms (b) use LED lamps (c) use daylight to read (d) use old filament bulbs
12. 12.Which of these wastes electricity? (a) unplug idle chargers (b) use LED lamps (c) use daylight to read (d) leave fridge door open
13. 13.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 volt (c) 1 kilowatt-hour (kWh) (d) 1 ampere
14. 14.🧾 A family uses 40 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
15. 15.Which of these wastes electricity? (a) unplug idle chargers (b) use LED lamps (c) run fans in empty rooms (d) set the AC to 24 °C
16. 16.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
17. 17.🔍 Which is the odd one out? (a) use old filament bulbs (b) iron one shirt at a time (c) leave fridge door open (d) unplug idle chargers
18. 18.🔍 Which is the odd one out? (a) run fans in empty rooms (b) leave the TV on standby (c) use daylight to read (d) use old filament bulbs
19. 19.🔍 Which is the odd one out? (a) switch off empty rooms (b) unplug idle chargers (c) use old filament bulbs (d) use daylight to read
20. 20.🧾 A 50 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
21. 21.💡 Does it save or waste electricity to iron one shirt at a time? (a) saves electricity (b) wastes electricity
22. 22.🧾 A 100 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
23. 23.Which of these saves electricity? (a) use daylight to read (b) iron one shirt at a time (c) leave fridge door open (d) run fans in empty rooms
24. 24.Which of these saves electricity? (a) iron one shirt at a time (b) leave the TV on standby (c) close the fridge quickly (d) leave fridge door open
25. 25.Which of these saves electricity? (a) unplug idle chargers (b) use old filament bulbs (c) iron one shirt at a time (d) leave fridge door open
26. 26.🔍 Which is the odd one out? (a) close the fridge quickly (b) use daylight to read (c) unplug idle chargers (d) leave fridge door open
27. 27.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 7 hours. How many watt-hours (Wh) are saved?
28. 28.Which of these wastes electricity? (a) leave the TV on standby (b) unplug idle chargers (c) use LED lamps (d) set the AC to 24 °C
29. 29.🧾 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
30. 30.True or false: to use old filament bulbs saves electricity. (a) True (b) False
31. 31.💡 Does it save or waste electricity to unplug idle chargers? (a) saves electricity (b) wastes electricity
32. 32.True or false: to close the fridge quickly saves electricity. (a) False (b) True
33. 33.🧾 A 50 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
34. 34.🧾 A family uses 100 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
35. 35.🧾 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?
36. 36.Which of these saves electricity? (a) leave the TV on standby (b) set the AC to 24 °C (c) use old filament bulbs (d) run fans in empty rooms
37. 37.True or false: to unplug idle chargers saves electricity. (a) True (b) False
38. 38.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
39. 39.🧾 A 1500 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
40. 40.Which of these wastes electricity? (a) iron one shirt at a time (b) use daylight to read (c) switch off empty rooms (d) use LED lamps

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