Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 77 · 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.🧾 Which lamp gives the same light for the least power? (a) a candle (b) an oil lamp (c) a filament bulb (d) an LED lamp
2. 2.🧾 A 250 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
3. 3.True or false: to leave fridge door open saves electricity. (a) True (b) False
4. 4.🔍 Which is the odd one out? (a) use LED lamps (b) unplug idle chargers (c) iron one shirt at a time (d) set the AC to 24 °C
5. 5.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 volt (c) 1 kilowatt-hour (kWh) (d) 1 ampere
6. 6.🧾 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?
7. 7.💡 Does it save or waste electricity to close the fridge quickly? (a) wastes electricity (b) saves electricity
8. 8.🔍 Which is the odd one out? (a) use old filament bulbs (b) leave the TV on standby (c) switch off empty rooms (d) leave fridge door open
9. 9.🧾 A 200 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
10. 10.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
11. 11.🔍 Which is the odd one out? (a) leave the TV on standby (b) switch off empty rooms (c) unplug idle chargers (d) use daylight to read
12. 12.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
13. 13.🧾 A family uses 190 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
14. 14.🧾 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?
15. 15.True or false: to switch off empty rooms wastes electricity. (a) True (b) False
16. 16.Which of these saves electricity? (a) use old filament bulbs (b) leave fridge door open (c) iron one shirt at a time (d) close the fridge quickly
17. 17.🧾 A 100 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
18. 18.Which of these saves electricity? (a) iron one shirt at a time (b) switch off empty rooms (c) leave the TV on standby (d) use old filament bulbs
19. 19.True or false: to leave the TV on standby wastes electricity. (a) False (b) True
20. 20.🧾 A family uses 60 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
21. 21.🔍 Which is the odd one out? (a) use old filament bulbs (b) leave fridge door open (c) unplug idle chargers (d) leave the TV on standby
22. 22.💡 Does it save or waste electricity to set the AC to 24 °C? (a) saves electricity (b) wastes electricity
23. 23.💡 Does it save or waste electricity to use LED lamps? (a) saves electricity (b) wastes electricity
24. 24.True or false: to switch off empty rooms saves electricity. (a) False (b) True
25. 25.True or false: to iron one shirt at a time wastes electricity. (a) False (b) True
26. 26.True or false: to unplug idle chargers saves electricity. (a) False (b) True
27. 27.🧾 A 50 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
28. 28.True or false: to use LED lamps saves electricity. (a) True (b) False
29. 29.Which of these wastes electricity? (a) unplug idle chargers (b) set the AC to 24 °C (c) switch off empty rooms (d) leave fridge door open
30. 30.Which of these saves electricity? (a) iron one shirt at a time (b) leave fridge door open (c) run fans in empty rooms (d) use daylight to read
31. 31.🧾 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?
32. 32.🧾 A 100 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
33. 33.True or false: to close the fridge quickly wastes electricity. (a) True (b) False
34. 34.🧾 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?
35. 35.🧾 A 200 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
36. 36.🧾 A family uses 150 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
37. 37.True or false: to unplug idle chargers wastes electricity. (a) False (b) True
38. 38.🧾 A 1500 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
39. 39.🔍 Which is the odd one out? (a) leave fridge door open (b) use daylight to read (c) switch off empty rooms (d) use LED lamps
40. 40.💡 Does it save or waste electricity to run fans in empty rooms? (a) wastes electricity (b) saves electricity

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