Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 251 · 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 leave fridge door open wastes electricity. (a) True (b) False
2. 2.🔍 Which is the odd one out? (a) switch off empty rooms (b) use LED lamps (c) use daylight to read (d) iron one shirt at a time
3. 3.Which of these wastes electricity? (a) use LED lamps (b) set the AC to 24 °C (c) run fans in empty rooms (d) close the fridge quickly
4. 4.🔍 Which is the odd one out? (a) set the AC to 24 °C (b) use LED lamps (c) leave the TV on standby (d) unplug idle chargers
5. 5.💡 Does it save or waste electricity to use old filament bulbs? (a) saves electricity (b) wastes electricity
6. 6.🧾 A 250 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
7. 7.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
8. 8.🔍 Which is the odd one out? (a) leave fridge door open (b) set the AC to 24 °C (c) iron one shirt at a time (d) leave the TV on standby
9. 9.Which of these wastes electricity? (a) use daylight to read (b) set the AC to 24 °C (c) switch off empty rooms (d) leave the TV on standby
10. 10.💡 Does it save or waste electricity to run fans in empty rooms? (a) saves electricity (b) wastes electricity
11. 11.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
12. 12.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) an oil lamp (c) an LED lamp (d) a candle
13. 13.True or false: to unplug idle chargers wastes electricity. (a) True (b) False
14. 14.True or false: to set the AC to 24 °C wastes electricity. (a) True (b) False
15. 15.Which of these saves electricity? (a) leave the TV on standby (b) close the fridge quickly (c) run fans in empty rooms (d) use old filament bulbs
16. 16.True or false: to use LED lamps wastes electricity. (a) True (b) False
17. 17.True or false: to close the fridge quickly saves electricity. (a) False (b) True
18. 18.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
19. 19.💡 Does it save or waste electricity to close the fridge quickly? (a) saves electricity (b) wastes electricity
20. 20.🧾 A 250 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
21. 21.🧾 A 1500 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
22. 22.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
23. 23.Which of these saves electricity? (a) run fans in empty rooms (b) leave fridge door open (c) switch off empty rooms (d) use old filament bulbs
24. 24.Which of these saves electricity? (a) use LED lamps (b) leave fridge door open (c) run fans in empty rooms (d) iron one shirt at a time
25. 25.🔍 Which is the odd one out? (a) leave the TV on standby (b) run fans in empty rooms (c) leave fridge door open (d) use LED lamps
26. 26.🧾 A family uses 70 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
27. 27.True or false: to run fans in empty rooms wastes electricity. (a) False (b) True
28. 28.🧾 A 100 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
29. 29.🧾 A family uses 120 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
30. 30.🧾 A family uses 20 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
31. 31.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 ampere (c) 1 kilowatt-hour (kWh) (d) 1 watt
32. 32.🧾 A 50 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
33. 33.💡 Does it save or waste electricity to unplug idle chargers? (a) wastes electricity (b) saves electricity
34. 34.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 2 hours. How many watt-hours (Wh) are saved?
35. 35.🧾 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?
36. 36.🔍 Which is the odd one out? (a) use daylight to read (b) run fans in empty rooms (c) close the fridge quickly (d) unplug idle chargers
37. 37.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 10 hours. How many watt-hours (Wh) are saved?
38. 38.🔍 Which is the odd one out? (a) switch off empty rooms (b) leave fridge door open (c) set the AC to 24 °C (d) use daylight to read
39. 39.💡 Does it save or waste electricity to leave the TV on standby? (a) saves electricity (b) wastes electricity
40. 40.🧾 A 250 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =

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