Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 720 · 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 3 hours. How many watt-hours (Wh) are saved?
2. 2.Which of these wastes electricity? (a) use daylight to read (b) run fans in empty rooms (c) switch off empty rooms (d) use LED lamps
3. 3.🧾 A 200 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
4. 4.🧾 A 2000 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
5. 5.💡 Does it save or waste electricity to set the AC to 24 °C? (a) saves electricity (b) wastes electricity
6. 6.🔍 Which is the odd one out? (a) use old filament bulbs (b) leave fridge door open (c) close the fridge quickly (d) leave the TV on standby
7. 7.🧾 A family uses 150 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
8. 8.Which of these saves electricity? (a) run fans in empty rooms (b) close the fridge quickly (c) leave the TV on standby (d) iron one shirt at a time
9. 9.🔍 Which is the odd one out? (a) unplug idle chargers (b) switch off empty rooms (c) close the fridge quickly (d) iron one shirt at a time
10. 10.True or false: to use daylight to read saves electricity. (a) True (b) False
11. 11.🧾 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?
12. 12.Which of these wastes electricity? (a) unplug idle chargers (b) use old filament bulbs (c) switch off empty rooms (d) use daylight to read
13. 13.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 watt (c) 1 volt (d) 1 kilowatt-hour (kWh)
14. 14.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
15. 15.True or false: to leave the TV on standby saves electricity. (a) False (b) True
16. 16.🔍 Which is the odd one out? (a) leave the TV on standby (b) leave fridge door open (c) unplug idle chargers (d) use old filament bulbs
17. 17.💡 Does it save or waste electricity to unplug idle chargers? (a) saves electricity (b) wastes electricity
18. 18.True or false: to close the fridge quickly saves electricity. (a) True (b) False
19. 19.🧾 A 250 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
20. 20.Which of these saves electricity? (a) run fans in empty rooms (b) use old filament bulbs (c) iron one shirt at a time (d) set the AC to 24 °C
21. 21.True or false: to switch off empty rooms wastes electricity. (a) True (b) False
22. 22.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
23. 23.🧾 A family uses 30 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
24. 24.🧾 Which lamp gives the same light for the least power? (a) an LED lamp (b) an oil lamp (c) a candle (d) a filament bulb
25. 25.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
26. 26.🧾 A 50 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
27. 27.🧾 A 1500 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
28. 28.🧾 A 50 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
29. 29.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 2 hours. How many watt-hours (Wh) are saved?
30. 30.💡 Does it save or waste electricity to leave fridge door open? (a) wastes electricity (b) saves electricity
31. 31.True or false: to close the fridge quickly wastes electricity. (a) True (b) False
32. 32.🔍 Which is the odd one out? (a) use LED lamps (b) switch off empty rooms (c) unplug idle chargers (d) leave fridge door open
33. 33.🧾 A family uses 30 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
34. 34.Which of these wastes electricity? (a) close the fridge quickly (b) use LED lamps (c) iron one shirt at a time (d) use daylight to read
35. 35.🧾 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?
36. 36.🔍 Which is the odd one out? (a) leave the TV on standby (b) run fans in empty rooms (c) use LED lamps (d) leave fridge door open
37. 37.🧾 A 200 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
38. 38.True or false: to use old filament bulbs saves electricity. (a) False (b) True
39. 39.💡 Does it save or waste electricity to use old filament bulbs? (a) saves electricity (b) wastes electricity
40. 40.🧾 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?

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