Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 287 · 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.🔍 Which is the odd one out? (a) close the fridge quickly (b) switch off empty rooms (c) run fans in empty rooms (d) unplug idle chargers
2. 2.True or false: to switch off empty rooms saves electricity. (a) False (b) True
3. 3.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 5 hours. How many watt-hours (Wh) are saved?
4. 4.🧾 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?
5. 5.🧾 A 50 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
6. 6.🧾 A 2000 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
7. 7.🧾 A family uses 180 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
8. 8.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 6 hours. How many watt-hours (Wh) are saved?
9. 9.💡 Does it save or waste electricity to iron one shirt at a time? (a) saves electricity (b) wastes electricity
10. 10.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 ampere (c) 1 volt (d) 1 kilowatt-hour (kWh)
11. 11.🧾 A 100 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
12. 12.🧾 A 2000 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
13. 13.💡 Does it save or waste electricity to unplug idle chargers? (a) wastes electricity (b) saves electricity
14. 14.🧾 A 250 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
15. 15.🧾 A 250 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
16. 16.Which of these wastes electricity? (a) use old filament bulbs (b) close the fridge quickly (c) use LED lamps (d) use daylight to read
17. 17.🧾 A 1000 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
18. 18.Which of these wastes electricity? (a) iron one shirt at a time (b) use LED lamps (c) close the fridge quickly (d) switch off empty rooms
19. 19.True or false: to set the AC to 24 °C wastes electricity. (a) False (b) True
20. 20.🧾 A family uses 150 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
21. 21.🧾 A 500 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
22. 22.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) an LED lamp (c) a candle (d) a filament bulb
23. 23.Which of these saves electricity? (a) close the fridge quickly (b) leave fridge door open (c) iron one shirt at a time (d) leave the TV on standby
24. 24.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 10 hours. How many watt-hours (Wh) are saved?
25. 25.💡 Does it save or waste electricity to switch off empty rooms? (a) saves electricity (b) wastes electricity
26. 26.Which of these saves electricity? (a) use LED lamps (b) leave the TV on standby (c) run fans in empty rooms (d) use old filament bulbs
27. 27.🧾 A 50 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
28. 28.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
29. 29.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
30. 30.True or false: to use daylight to read wastes electricity. (a) True (b) False
31. 31.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
32. 32.True or false: to leave the TV on standby saves electricity. (a) True (b) False
33. 33.Which of these wastes electricity? (a) run fans in empty rooms (b) switch off empty rooms (c) use daylight to read (d) close the fridge quickly
34. 34.🧾 A family uses 70 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
35. 35.🔍 Which is the odd one out? (a) leave fridge door open (b) use daylight to read (c) use old filament bulbs (d) run fans in empty rooms
36. 36.💡 Does it save or waste electricity to run fans in empty rooms? (a) saves electricity (b) wastes electricity
37. 37.Which of these saves electricity? (a) iron one shirt at a time (b) leave the TV on standby (c) unplug idle chargers (d) use old filament bulbs
38. 38.Which of these wastes electricity? (a) leave the TV on standby (b) set the AC to 24 °C (c) use daylight to read (d) close the fridge quickly
39. 39.Which of these wastes electricity? (a) set the AC to 24 °C (b) use daylight to read (c) leave fridge door open (d) unplug idle chargers
40. 40.🧾 A family uses 30 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?

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