Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 310 · 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 wastes electricity. (a) True (b) False
2. 2.Which of these wastes electricity? (a) use LED lamps (b) leave fridge door open (c) unplug idle chargers (d) switch off empty rooms
3. 3.Which of these saves electricity? (a) run fans in empty rooms (b) leave the TV on standby (c) unplug idle chargers (d) leave fridge door open
4. 4.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
5. 5.🧾 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?
6. 6.True or false: to set the AC to 24 °C saves electricity. (a) False (b) True
7. 7.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
8. 8.Which of these wastes electricity? (a) set the AC to 24 °C (b) switch off empty rooms (c) use old filament bulbs (d) use LED lamps
9. 9.🧾 A 100 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
10. 10.💡 Does it save or waste electricity to unplug idle chargers? (a) saves electricity (b) wastes electricity
11. 11.🧾 A 200 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
12. 12.🧾 A 200 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
13. 13.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
14. 14.🧾 A family uses 110 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
15. 15.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
16. 16.🔍 Which is the odd one out? (a) set the AC to 24 °C (b) run fans in empty rooms (c) close the fridge quickly (d) switch off empty rooms
17. 17.💡 Does it save or waste electricity to use old filament bulbs? (a) saves electricity (b) wastes electricity
18. 18.🧾 A 2000 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
19. 19.Which of these saves electricity? (a) use old filament bulbs (b) leave fridge door open (c) set the AC to 24 °C (d) leave the TV on standby
20. 20.True or false: to close the fridge quickly wastes electricity. (a) True (b) False
21. 21.🧾 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?
22. 22.🧾 A family uses 190 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
23. 23.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) unplug idle chargers
24. 24.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
25. 25.🧾 Which lamp gives the same light for the least power? (a) a candle (b) a filament bulb (c) an LED lamp (d) an oil lamp
26. 26.🧾 A family uses 60 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
27. 27.True or false: to use old filament bulbs saves electricity. (a) True (b) False
28. 28.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 volt (c) 1 ampere (d) 1 kilowatt-hour (kWh)
29. 29.True or false: to close the fridge quickly saves electricity. (a) False (b) True
30. 30.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 6 hours. How many watt-hours (Wh) are saved?
31. 31.🧾 A family uses 80 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
32. 32.True or false: to leave fridge door open saves electricity. (a) True (b) False
33. 33.💡 Does it save or waste electricity to run fans in empty rooms? (a) saves electricity (b) wastes electricity
34. 34.🧾 A 2000 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
35. 35.🧾 A 50 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
36. 36.🔍 Which is the odd one out? (a) leave the TV on standby (b) use LED lamps (c) set the AC to 24 °C (d) switch off empty rooms
37. 37.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
38. 38.🧾 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?
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 10 hours. How many watt-hours (Wh) are saved?
40. 40.True or false: to use old filament bulbs wastes electricity. (a) False (b) True

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