Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 345 · 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 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?
2. 2.True or false: to unplug idle chargers wastes electricity. (a) True (b) False
3. 3.💡 Does it save or waste electricity to close the fridge quickly? (a) saves electricity (b) wastes electricity
4. 4.Which of these saves electricity? (a) leave fridge door open (b) iron one shirt at a time (c) close the fridge quickly (d) use old filament bulbs
5. 5.🧾 A 200 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
6. 6.🔍 Which is the odd one out? (a) leave fridge door open (b) iron one shirt at a time (c) use LED lamps (d) leave the TV on standby
7. 7.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
8. 8.💡 Does it save or waste electricity to unplug idle chargers? (a) wastes electricity (b) saves electricity
9. 9.🧾 A 50 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
10. 10.Which of these saves electricity? (a) leave the TV on standby (b) use old filament bulbs (c) run fans in empty rooms (d) use daylight to read
11. 11.🧾 A 2000 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
12. 12.🧾 Which lamp gives the same light for the least power? (a) an LED lamp (b) an oil lamp (c) a filament bulb (d) a candle
13. 13.True or false: to iron one shirt at a time saves electricity. (a) True (b) False
14. 14.💡 Does it save or waste electricity to use daylight to read? (a) saves electricity (b) wastes electricity
15. 15.🔍 Which is the odd one out? (a) iron one shirt at a time (b) close the fridge quickly (c) set the AC to 24 °C (d) use LED lamps
16. 16.True or false: to leave the TV on standby saves electricity. (a) True (b) False
17. 17.🔍 Which is the odd one out? (a) use LED lamps (b) close the fridge quickly (c) unplug idle chargers (d) leave the TV on standby
18. 18.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
19. 19.🧾 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?
20. 20.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
21. 21.Which of these wastes electricity? (a) unplug idle chargers (b) close the fridge quickly (c) leave the TV on standby (d) use LED lamps
22. 22.💡 Does it save or waste electricity to run fans in empty rooms? (a) wastes electricity (b) saves electricity
23. 23.💡 Does it save or waste electricity to leave fridge door open? (a) wastes electricity (b) saves electricity
24. 24.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 volt (c) 1 ampere (d) 1 kilowatt-hour (kWh)
25. 25.🧾 A 1000 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
26. 26.Which of these saves electricity? (a) iron one shirt at a time (b) use old filament bulbs (c) unplug idle chargers (d) leave fridge door open
27. 27.🔍 Which is the odd one out? (a) use LED lamps (b) close the fridge quickly (c) unplug idle chargers (d) leave fridge door open
28. 28.True or false: to use daylight to read wastes electricity. (a) False (b) True
29. 29.🔍 Which is the odd one out? (a) run fans in empty rooms (b) leave the TV on standby (c) use daylight to read (d) iron one shirt at a time
30. 30.🧾 A 1500 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
31. 31.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
32. 32.True or false: to leave fridge door open wastes electricity. (a) False (b) True
33. 33.🧾 A family uses 110 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
34. 34.🧾 A family uses 150 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
35. 35.🧾 A 200 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
36. 36.🧾 A family uses 130 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
37. 37.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
38. 38.🧾 A 100 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
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.🔍 Which is the odd one out? (a) set the AC to 24 °C (b) use old filament bulbs (c) close the fridge quickly (d) switch off empty rooms

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