Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 470 · 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 500 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
2. 2.True or false: to switch off empty rooms saves electricity. (a) True (b) False
3. 3.🧾 A family uses 130 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
4. 4.🔍 Which is the odd one out? (a) close the fridge quickly (b) switch off empty rooms (c) use old filament bulbs (d) use LED lamps
5. 5.🧾 A family uses 140 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
6. 6.True or false: to leave the TV on standby saves electricity. (a) True (b) False
7. 7.🔍 Which is the odd one out? (a) run fans in empty rooms (b) set the AC to 24 °C (c) leave the TV on standby (d) use old filament bulbs
8. 8.True or false: to close the fridge quickly saves electricity. (a) True (b) False
9. 9.🧾 A 1500 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
10. 10.True or false: to use old filament bulbs saves electricity. (a) False (b) True
11. 11.🧾 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?
12. 12.Which of these wastes electricity? (a) use LED lamps (b) run fans in empty rooms (c) set the AC to 24 °C (d) switch off empty rooms
13. 13.💡 Does it save or waste electricity to run fans in empty rooms? (a) wastes electricity (b) saves electricity
14. 14.🧾 A 50 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
15. 15.True or false: to set the AC to 24 °C saves electricity. (a) False (b) True
16. 16.💡 Does it save or waste electricity to set the AC to 24 °C? (a) saves electricity (b) wastes electricity
17. 17.🧾 Which lamp gives the same light for the least power? (a) an LED lamp (b) a filament bulb (c) a candle (d) an oil lamp
18. 18.Which of these wastes electricity? (a) unplug idle chargers (b) close the fridge quickly (c) use daylight to read (d) leave the TV on standby
19. 19.💡 Does it save or waste electricity to iron one shirt at a time? (a) saves electricity (b) wastes electricity
20. 20.True or false: to unplug idle chargers wastes electricity. (a) False (b) True
21. 21.🧾 A 2000 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
22. 22.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 kilowatt-hour (kWh) (c) 1 ampere (d) 1 watt
23. 23.🧾 A 250 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
24. 24.True or false: to use LED lamps saves electricity. (a) False (b) True
25. 25.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 2 hours. How many watt-hours (Wh) are saved?
26. 26.🧾 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?
27. 27.💡 Does it save or waste electricity to close the fridge quickly? (a) saves electricity (b) wastes electricity
28. 28.🧾 A 200 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
29. 29.Which of these saves electricity? (a) leave the TV on standby (b) run fans in empty rooms (c) unplug idle chargers (d) leave fridge door open
30. 30.Which of these wastes electricity? (a) use daylight to read (b) switch off empty rooms (c) set the AC to 24 °C (d) leave fridge door open
31. 31.🔍 Which is the odd one out? (a) use LED lamps (b) leave the TV on standby (c) set the AC to 24 °C (d) switch off empty rooms
32. 32.Which of these wastes electricity? (a) use LED lamps (b) iron one shirt at a time (c) unplug idle chargers (d) close the fridge quickly
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 3 hours. How many watt-hours (Wh) are saved?
34. 34.🧾 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?
35. 35.🔍 Which is the odd one out? (a) use LED lamps (b) leave fridge door open (c) use daylight to read (d) set the AC to 24 °C
36. 36.💡 Does it save or waste electricity to leave the TV on standby? (a) saves electricity (b) wastes electricity
37. 37.💡 Does it save or waste electricity to switch off empty rooms? (a) saves electricity (b) wastes electricity
38. 38.🧾 A 100 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
39. 39.Which of these saves electricity? (a) leave fridge door open (b) use daylight to read (c) use old filament bulbs (d) run fans in empty rooms
40. 40.True or false: to switch off empty rooms wastes electricity. (a) False (b) True

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