Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 407 · 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 100 W filament bulb is swapped for a 15 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 family uses 200 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
3. 3.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
4. 4.🧾 A 500 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
5. 5.💡 Does it save or waste electricity to close the fridge quickly? (a) wastes electricity (b) saves electricity
6. 6.🔍 Which is the odd one out? (a) leave the TV on standby (b) iron one shirt at a time (c) use daylight to read (d) leave fridge door open
7. 7.Which of these wastes electricity? (a) use LED lamps (b) iron one shirt at a time (c) unplug idle chargers (d) switch off empty rooms
8. 8.True or false: to close the fridge quickly saves electricity. (a) True (b) False
9. 9.🧾 Which lamp gives the same light for the least power? (a) an LED lamp (b) a candle (c) a filament bulb (d) an oil lamp
10. 10.🧾 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?
11. 11.🧾 A 250 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
12. 12.True or false: to close the fridge quickly wastes electricity. (a) False (b) True
13. 13.🔍 Which is the odd one out? (a) leave the TV on standby (b) leave fridge door open (c) iron one shirt at a time (d) set the AC to 24 °C
14. 14.🔍 Which is the odd one out? (a) leave fridge door open (b) use LED lamps (c) iron one shirt at a time (d) use old filament bulbs
15. 15.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 watt (c) 1 ampere (d) 1 kilowatt-hour (kWh)
16. 16.🧾 A family uses 80 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
17. 17.🔍 Which is the odd one out? (a) run fans in empty rooms (b) leave fridge door open (c) switch off empty rooms (d) use old filament bulbs
18. 18.True or false: to iron one shirt at a time wastes electricity. (a) True (b) False
19. 19.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 6 hours. How many watt-hours (Wh) are saved?
20. 20.🧾 A 200 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
21. 21.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
22. 22.Which of these wastes electricity? (a) set the AC to 24 °C (b) use daylight to read (c) leave fridge door open (d) close the fridge quickly
23. 23.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
24. 24.True or false: to run fans in empty rooms wastes electricity. (a) True (b) False
25. 25.🧾 A family uses 70 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
26. 26.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 8 hours. How many watt-hours (Wh) are saved?
27. 27.🔍 Which is the odd one out? (a) close the fridge quickly (b) use old filament bulbs (c) set the AC to 24 °C (d) unplug idle chargers
28. 28.Which of these wastes electricity? (a) leave the TV on standby (b) use daylight to read (c) set the AC to 24 °C (d) close the fridge quickly
29. 29.Which of these wastes electricity? (a) close the fridge quickly (b) set the AC to 24 °C (c) unplug idle chargers (d) run fans in empty rooms
30. 30.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
31. 31.Which of these saves electricity? (a) use daylight to read (b) leave the TV on standby (c) use old filament bulbs (d) leave fridge door open
32. 32.True or false: to iron one shirt at a time saves electricity. (a) False (b) True
33. 33.🧾 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?
34. 34.True or false: to leave fridge door open wastes electricity. (a) False (b) True
35. 35.True or false: to use daylight to read saves electricity. (a) False (b) True
36. 36.💡 Does it save or waste electricity to run fans in empty rooms? (a) wastes electricity (b) saves electricity
37. 37.True or false: to leave the TV on standby wastes electricity. (a) False (b) True
38. 38.💡 Does it save or waste electricity to leave fridge door open? (a) saves electricity (b) wastes electricity
39. 39.🔍 Which is the odd one out? (a) use old filament bulbs (b) run fans in empty rooms (c) close the fridge quickly (d) leave fridge door open
40. 40.🧾 A family uses 150 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?

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