Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 641 · 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.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 1 hour. How many watt-hours (Wh) are saved?
2. 2.💡 Does it save or waste electricity to leave fridge door open? (a) wastes electricity (b) saves electricity
3. 3.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
4. 4.🧾 A 2000 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
5. 5.Which of these wastes electricity? (a) use daylight to read (b) use LED lamps (c) use old filament bulbs (d) close the fridge quickly
6. 6.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) a candle (c) an LED lamp (d) a filament bulb
7. 7.🧾 A 100 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
8. 8.Which of these wastes electricity? (a) switch off empty rooms (b) close the fridge quickly (c) set the AC to 24 °C (d) iron one shirt at a time
9. 9.Which of these wastes electricity? (a) set the AC to 24 °C (b) use daylight to read (c) unplug idle chargers (d) run fans in empty rooms
10. 10.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
11. 11.💡 Does it save or waste electricity to run fans in empty rooms? (a) saves electricity (b) wastes electricity
12. 12.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 ampere (c) 1 watt (d) 1 kilowatt-hour (kWh)
13. 13.🔍 Which is the odd one out? (a) leave the TV on standby (b) leave fridge door open (c) switch off empty rooms (d) run fans in empty rooms
14. 14.🧾 A 1000 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
15. 15.🧾 A 250 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
16. 16.🧾 A family uses 160 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
17. 17.Which of these saves electricity? (a) run fans in empty rooms (b) leave fridge door open (c) close the fridge quickly (d) leave the TV on standby
18. 18.🧾 A 100 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
19. 19.💡 Does it save or waste electricity to set the AC to 24 °C? (a) saves electricity (b) wastes electricity
20. 20.True or false: to use old filament bulbs wastes electricity. (a) False (b) True
21. 21.Which of these saves electricity? (a) leave the TV on standby (b) use old filament bulbs (c) use daylight to read (d) iron one shirt at a time
22. 22.True or false: to use LED lamps wastes electricity. (a) False (b) True
23. 23.True or false: to leave the TV on standby saves electricity. (a) True (b) False
24. 24.🧾 A 500 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
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 1 hour. How many watt-hours (Wh) are saved?
26. 26.🔍 Which is the odd one out? (a) leave fridge door open (b) leave the TV on standby (c) use old filament bulbs (d) unplug idle chargers
27. 27.🔍 Which is the odd one out? (a) use old filament bulbs (b) iron one shirt at a time (c) use daylight to read (d) leave the TV on standby
28. 28.🧾 A 1000 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
29. 29.True or false: to unplug idle chargers wastes electricity. (a) True (b) False
30. 30.💡 Does it save or waste electricity to use old filament bulbs? (a) saves electricity (b) wastes electricity
31. 31.🧾 A family uses 140 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
32. 32.🔍 Which is the odd one out? (a) use LED lamps (b) close the fridge quickly (c) use old filament bulbs (d) switch off empty rooms
33. 33.Which of these saves electricity? (a) leave fridge door open (b) leave the TV on standby (c) run fans in empty rooms (d) unplug idle chargers
34. 34.True or false: to close the fridge quickly saves electricity. (a) True (b) False
35. 35.🧾 A 200 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
36. 36.True or false: to iron one shirt at a time wastes electricity. (a) False (b) True
37. 37.🧾 A family uses 110 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
38. 38.🔍 Which is the odd one out? (a) use old filament bulbs (b) use LED lamps (c) iron one shirt at a time (d) leave the TV on standby
39. 39.💡 Does it save or waste electricity to close the fridge quickly? (a) wastes electricity (b) saves electricity
40. 40.🧾 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?

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