Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 636 · 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 4 hours. How many watt-hours (Wh) are saved?
2. 2.🧾 A 1500 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
3. 3.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
4. 4.True or false: to leave fridge door open wastes electricity. (a) False (b) True
5. 5.💡 Does it save or waste electricity to run fans in empty rooms? (a) wastes electricity (b) saves electricity
6. 6.True or false: to use LED lamps saves electricity. (a) True (b) False
7. 7.💡 Does it save or waste electricity to use daylight to read? (a) saves electricity (b) wastes electricity
8. 8.🔍 Which is the odd one out? (a) switch off empty rooms (b) run fans in empty rooms (c) leave fridge door open (d) leave the TV on standby
9. 9.🧾 A 500 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
10. 10.🔍 Which is the odd one out? (a) use LED lamps (b) close the fridge quickly (c) set the AC to 24 °C (d) run fans in empty rooms
11. 11.Which of these saves electricity? (a) leave fridge door open (b) leave the TV on standby (c) run fans in empty rooms (d) use daylight to read
12. 12.🧾 Which lamp gives the same light for the least power? (a) a candle (b) a filament bulb (c) an oil lamp (d) an LED lamp
13. 13.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 8 hours. How many watt-hours (Wh) are saved?
14. 14.💡 Does it save or waste electricity to iron one shirt at a time? (a) saves electricity (b) wastes electricity
15. 15.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 kilowatt-hour (kWh) (c) 1 watt (d) 1 ampere
16. 16.💡 Does it save or waste electricity to leave fridge door open? (a) wastes electricity (b) saves electricity
17. 17.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 3 hours. How many watt-hours (Wh) are saved?
18. 18.True or false: to close the fridge quickly wastes electricity. (a) False (b) True
19. 19.🧾 A 1000 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
20. 20.🧾 A family uses 20 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
21. 21.Which of these wastes electricity? (a) use daylight to read (b) use LED lamps (c) close the fridge quickly (d) leave fridge door open
22. 22.Which of these saves electricity? (a) iron one shirt at a time (b) leave fridge door open (c) leave the TV on standby (d) use LED lamps
23. 23.💡 Does it save or waste electricity to switch off empty rooms? (a) saves electricity (b) wastes electricity
24. 24.True or false: to leave the TV on standby saves electricity. (a) False (b) True
25. 25.🔍 Which is the odd one out? (a) leave fridge door open (b) run fans in empty rooms (c) set the AC to 24 °C (d) iron one shirt at a time
26. 26.🧾 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?
27. 27.Which of these wastes electricity? (a) unplug idle chargers (b) run fans in empty rooms (c) use LED lamps (d) close the fridge quickly
28. 28.Which of these saves electricity? (a) use old filament bulbs (b) leave the TV on standby (c) iron one shirt at a time (d) unplug idle chargers
29. 29.🧾 A 500 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
30. 30.🔍 Which is the odd one out? (a) leave the TV on standby (b) use daylight to read (c) iron one shirt at a time (d) leave fridge door open
31. 31.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 7 hours. How many watt-hours (Wh) are saved?
32. 32.💡 Does it save or waste electricity to use LED lamps? (a) saves electricity (b) wastes electricity
33. 33.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
34. 34.🧾 A 200 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
35. 35.💡 Does it save or waste electricity to use old filament bulbs? (a) saves electricity (b) wastes electricity
36. 36.🔍 Which is the odd one out? (a) unplug idle chargers (b) use LED lamps (c) use daylight to read (d) iron one shirt at a time
37. 37.Which of these wastes electricity? (a) set the AC to 24 °C (b) close the fridge quickly (c) iron one shirt at a time (d) use LED lamps
38. 38.🧾 A family uses 190 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
39. 39.🧾 A 2000 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
40. 40.True or false: to switch off empty rooms wastes electricity. (a) True (b) False

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