Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 730 · 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 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?
2. 2.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
3. 3.💡 Does it save or waste electricity to close the fridge quickly? (a) saves electricity (b) wastes electricity
4. 4.💡 Does it save or waste electricity to switch off empty rooms? (a) saves electricity (b) wastes electricity
5. 5.True or false: to iron one shirt at a time wastes electricity. (a) True (b) False
6. 6.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 ampere (c) 1 volt (d) 1 kilowatt-hour (kWh)
7. 7.Which of these saves electricity? (a) iron one shirt at a time (b) run fans in empty rooms (c) switch off empty rooms (d) leave fridge door open
8. 8.🧾 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
9. 9.💡 Does it save or waste electricity to use daylight to read? (a) saves electricity (b) wastes electricity
10. 10.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
11. 11.🧾 A 2000 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
12. 12.Which of these wastes electricity? (a) leave fridge door open (b) use LED lamps (c) unplug idle chargers (d) use daylight to read
13. 13.Which of these wastes electricity? (a) close the fridge quickly (b) switch off empty rooms (c) use LED lamps (d) use old filament bulbs
14. 14.💡 Does it save or waste electricity to iron one shirt at a time? (a) saves electricity (b) wastes electricity
15. 15.🧾 A 200 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
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 LED lamps (b) close the fridge quickly (c) switch off empty rooms (d) iron one shirt at a time
18. 18.Which of these saves electricity? (a) use daylight to read (b) iron one shirt at a time (c) leave fridge door open (d) run fans in empty rooms
19. 19.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
20. 20.🔍 Which is the odd one out? (a) run fans in empty rooms (b) leave fridge door open (c) unplug idle chargers (d) leave the TV on standby
21. 21.Which of these saves electricity? (a) leave fridge door open (b) leave the TV on standby (c) iron one shirt at a time (d) use LED lamps
22. 22.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 6 hours. How many watt-hours (Wh) are saved?
23. 23.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 8 hours. How many watt-hours (Wh) are saved?
24. 24.True or false: to use daylight to read wastes electricity. (a) False (b) True
25. 25.Which of these wastes electricity? (a) switch off empty rooms (b) run fans in empty rooms (c) set the AC to 24 °C (d) close the fridge quickly
26. 26.Which of these wastes electricity? (a) use daylight to read (b) use LED lamps (c) switch off empty rooms (d) iron one shirt at a time
27. 27.🔍 Which is the odd one out? (a) switch off empty rooms (b) close the fridge quickly (c) leave the TV on standby (d) unplug idle chargers
28. 28.🧾 A family uses 170 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
29. 29.🔍 Which is the odd one out? (a) leave fridge door open (b) close the fridge quickly (c) use LED lamps (d) set the AC to 24 °C
30. 30.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 5 hours. How many watt-hours (Wh) are saved?
31. 31.True or false: to leave the TV on standby saves electricity. (a) False (b) True
32. 32.True or false: to switch off empty rooms wastes electricity. (a) False (b) True
33. 33.True or false: to close the fridge quickly saves electricity. (a) False (b) True
34. 34.True or false: to run fans in empty rooms wastes electricity. (a) False (b) True
35. 35.True or false: to run fans in empty rooms saves electricity. (a) True (b) False
36. 36.🧾 A 50 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
37. 37.🧾 A family uses 70 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
38. 38.True or false: to use old filament bulbs wastes electricity. (a) True (b) False
39. 39.🧾 A family uses 190 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
40. 40.🧾 A 1000 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =

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