Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 408 · 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 7 hours. How many watt-hours (Wh) are saved?
2. 2.🧾 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?
3. 3.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 ampere (c) 1 watt (d) 1 kilowatt-hour (kWh)
4. 4.🧾 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
5. 5.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
6. 6.💡 Does it save or waste electricity to unplug idle chargers? (a) wastes electricity (b) saves electricity
7. 7.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
8. 8.🧾 A 200 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
9. 9.🔍 Which is the odd one out? (a) leave the TV on standby (b) run fans in empty rooms (c) use old filament bulbs (d) unplug idle chargers
10. 10.True or false: to close the fridge quickly saves electricity. (a) False (b) True
11. 11.🔍 Which is the odd one out? (a) use old filament bulbs (b) iron one shirt at a time (c) switch off empty rooms (d) leave fridge door open
12. 12.💡 Does it save or waste electricity to use LED lamps? (a) saves electricity (b) wastes electricity
13. 13.True or false: to switch off empty rooms wastes electricity. (a) False (b) True
14. 14.🧾 A 2000 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
15. 15.True or false: to leave the TV on standby saves electricity. (a) True (b) False
16. 16.Which of these wastes electricity? (a) switch off empty rooms (b) set the AC to 24 °C (c) leave the TV on standby (d) use LED lamps
17. 17.True or false: to leave fridge door open saves electricity. (a) True (b) False
18. 18.Which of these saves electricity? (a) leave the TV on standby (b) leave fridge door open (c) use old filament bulbs (d) switch off empty rooms
19. 19.🧾 A family uses 90 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
20. 20.🧾 A 2000 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
21. 21.🧾 A family uses 60 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
22. 22.🧾 A family uses 80 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
23. 23.🧾 A 1000 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
24. 24.Which of these saves electricity? (a) use old filament bulbs (b) run fans in empty rooms (c) leave fridge door open (d) set the AC to 24 °C
25. 25.True or false: to unplug idle chargers saves electricity. (a) False (b) True
26. 26.True or false: to set the AC to 24 °C saves electricity. (a) False (b) True
27. 27.True or false: to leave fridge door open wastes electricity. (a) False (b) True
28. 28.🧾 A 2000 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
29. 29.🧾 A 1500 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
30. 30.Which of these saves electricity? (a) close the fridge quickly (b) iron one shirt at a time (c) run fans in empty rooms (d) leave fridge door open
31. 31.🧾 A family uses 20 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
32. 32.🧾 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?
33. 33.🧾 A family uses 140 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
34. 34.True or false: to use daylight to read saves electricity. (a) False (b) True
35. 35.🧾 A family uses 50 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
36. 36.🧾 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?
37. 37.💡 Does it save or waste electricity to iron one shirt at a time? (a) saves electricity (b) wastes electricity
38. 38.Which of these saves electricity? (a) leave fridge door open (b) unplug idle chargers (c) iron one shirt at a time (d) use old filament bulbs
39. 39.🧾 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?
40. 40.True or false: to use daylight to read wastes electricity. (a) True (b) False

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