Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 425 · 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 iron one shirt at a time saves electricity. (a) True (b) False
2. 2.True or false: to run fans in empty rooms wastes electricity. (a) True (b) False
3. 3.🔍 Which is the odd one out? (a) use daylight to read (b) leave the TV on standby (c) run fans in empty rooms (d) leave fridge door open
4. 4.🧾 Which lamp gives the same light for the least power? (a) a candle (b) an oil lamp (c) a filament bulb (d) an LED lamp
5. 5.💡 Does it save or waste electricity to switch off empty rooms? (a) saves electricity (b) wastes electricity
6. 6.🔍 Which is the odd one out? (a) use daylight to read (b) use LED lamps (c) leave fridge door open (d) close the fridge quickly
7. 7.💡 Does it save or waste electricity to run fans in empty rooms? (a) wastes electricity (b) saves electricity
8. 8.🧾 A 500 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
9. 9.🔍 Which is the odd one out? (a) use old filament bulbs (b) switch off empty rooms (c) run fans in empty rooms (d) leave fridge door open
10. 10.🧾 A 200 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
11. 11.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 6 hours. How many watt-hours (Wh) are saved?
12. 12.🧾 A 250 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
13. 13.🧾 A family uses 50 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
14. 14.🧾 A family uses 80 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
15. 15.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
16. 16.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 3 hours. How many watt-hours (Wh) are saved?
17. 17.🔍 Which is the odd one out? (a) use old filament bulbs (b) leave the TV on standby (c) run fans in empty rooms (d) set the AC to 24 °C
18. 18.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 5 hours. How many watt-hours (Wh) are saved?
19. 19.Which of these saves electricity? (a) use old filament bulbs (b) use daylight to read (c) leave fridge door open (d) iron one shirt at a time
20. 20.💡 Does it save or waste electricity to leave fridge door open? (a) saves electricity (b) wastes electricity
21. 21.🔍 Which is the odd one out? (a) use old filament bulbs (b) iron one shirt at a time (c) leave fridge door open (d) use LED lamps
22. 22.🧾 A family uses 20 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
23. 23.True or false: to use daylight to read saves electricity. (a) False (b) True
24. 24.🧾 A 2000 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
25. 25.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
26. 26.🔍 Which is the odd one out? (a) unplug idle chargers (b) set the AC to 24 °C (c) switch off empty rooms (d) use old filament bulbs
27. 27.Which of these wastes electricity? (a) unplug idle chargers (b) set the AC to 24 °C (c) leave the TV on standby (d) switch off empty rooms
28. 28.🔍 Which is the odd one out? (a) switch off empty rooms (b) close the fridge quickly (c) set the AC to 24 °C (d) run fans in empty rooms
29. 29.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 kilowatt-hour (kWh) (c) 1 volt (d) 1 watt
30. 30.💡 Does it save or waste electricity to set the AC to 24 °C? (a) saves electricity (b) wastes electricity
31. 31.🧾 A 250 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
32. 32.🔍 Which is the odd one out? (a) use LED lamps (b) iron one shirt at a time (c) use daylight to read (d) set the AC to 24 °C
33. 33.True or false: to close the fridge quickly saves electricity. (a) True (b) False
34. 34.True or false: to use LED lamps wastes electricity. (a) True (b) False
35. 35.🔍 Which is the odd one out? (a) unplug idle chargers (b) leave the TV on standby (c) leave fridge door open (d) run fans in empty rooms
36. 36.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
37. 37.True or false: to use old filament bulbs wastes electricity. (a) False (b) True
38. 38.Which of these wastes electricity? (a) set the AC to 24 °C (b) leave fridge door open (c) unplug idle chargers (d) use LED lamps
39. 39.🧾 A family uses 200 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
40. 40.Which of these saves electricity? (a) iron one shirt at a time (b) leave fridge door open (c) switch off empty rooms (d) leave the TV on standby

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