Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 81 · 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 switch off empty rooms saves electricity. (a) True (b) False
2. 2.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 3 hours. How many watt-hours (Wh) are saved?
3. 3.🧾 A family uses 100 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
4. 4.🧾 A 500 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
5. 5.Which of these saves electricity? (a) iron one shirt at a time (b) run fans in empty rooms (c) use old filament bulbs (d) use daylight to read
6. 6.🔍 Which is the odd one out? (a) use old filament bulbs (b) unplug idle chargers (c) use LED lamps (d) close the fridge quickly
7. 7.🔍 Which is the odd one out? (a) unplug idle chargers (b) use LED lamps (c) set the AC to 24 °C (d) leave the TV on standby
8. 8.True or false: to set the AC to 24 °C saves electricity. (a) True (b) False
9. 9.🔍 Which is the odd one out? (a) iron one shirt at a time (b) set the AC to 24 °C (c) use daylight to read (d) close the fridge quickly
10. 10.💡 Does it save or waste electricity to unplug idle chargers? (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.🧾 A 50 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
13. 13.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
14. 14.True or false: to run fans in empty rooms wastes electricity. (a) False (b) True
15. 15.True or false: to switch off empty rooms wastes electricity. (a) True (b) False
16. 16.Which of these saves electricity? (a) unplug idle chargers (b) leave the TV on standby (c) leave fridge door open (d) run fans in empty rooms
17. 17.Which of these wastes electricity? (a) leave the TV on standby (b) use LED lamps (c) close the fridge quickly (d) use daylight to read
18. 18.Which of these saves electricity? (a) use old filament bulbs (b) close the fridge quickly (c) iron one shirt at a time (d) leave the TV on standby
19. 19.Which of these saves electricity? (a) iron one shirt at a time (b) use LED lamps (c) leave the TV on standby (d) leave fridge door open
20. 20.🧾 A 1000 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
21. 21.🧾 A family uses 100 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
22. 22.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 watt (c) 1 kilowatt-hour (kWh) (d) 1 volt
23. 23.Which of these wastes electricity? (a) leave fridge door open (b) use daylight to read (c) switch off empty rooms (d) unplug idle chargers
24. 24.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) an oil lamp (c) a candle (d) an LED lamp
25. 25.🧾 A 100 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
26. 26.🧾 A 200 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
27. 27.🧾 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?
28. 28.🧾 A 1500 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
29. 29.🧾 A family uses 30 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
30. 30.🧾 A family uses 190 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
31. 31.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 2 hours. How many watt-hours (Wh) are saved?
32. 32.True or false: to use old filament bulbs saves electricity. (a) True (b) False
33. 33.Which of these saves electricity? (a) switch off empty rooms (b) leave the TV on standby (c) leave fridge door open (d) use old filament bulbs
34. 34.🧾 A 100 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
35. 35.🔍 Which is the odd one out? (a) unplug idle chargers (b) switch off empty rooms (c) use daylight to read (d) run fans in empty rooms
36. 36.🧾 A family uses 180 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
37. 37.Which of these wastes electricity? (a) close the fridge quickly (b) iron one shirt at a time (c) use LED lamps (d) switch off empty rooms
38. 38.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
39. 39.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
40. 40.True or false: to use old filament bulbs wastes electricity. (a) True (b) False

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