Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 941 · 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.🧾 A 2000 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
3. 3.🧾 A 2000 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
4. 4.🧾 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
5. 5.🧾 A 250 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
6. 6.🔍 Which is the odd one out? (a) close the fridge quickly (b) use LED lamps (c) switch off empty rooms (d) use old filament bulbs
7. 7.💡 Does it save or waste electricity to leave the TV on standby? (a) saves electricity (b) wastes electricity
8. 8.💡 Does it save or waste electricity to iron one shirt at a time? (a) saves electricity (b) wastes electricity
9. 9.💡 Does it save or waste electricity to unplug idle chargers? (a) wastes electricity (b) saves electricity
10. 10.🔍 Which is the odd one out? (a) unplug idle chargers (b) close the fridge quickly (c) leave fridge door open (d) use daylight to read
11. 11.💡 Does it save or waste electricity to use LED lamps? (a) saves electricity (b) wastes electricity
12. 12.💡 Does it save or waste electricity to close the fridge quickly? (a) wastes electricity (b) saves electricity
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 old filament bulbs? (a) wastes electricity (b) saves electricity
15. 15.True or false: to use daylight to read wastes electricity. (a) True (b) False
16. 16.True or false: to close the fridge quickly wastes electricity. (a) False (b) True
17. 17.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 ampere (c) 1 kilowatt-hour (kWh) (d) 1 watt
18. 18.🧾 A 200 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
19. 19.Which of these saves electricity? (a) switch off empty rooms (b) use old filament bulbs (c) leave fridge door open (d) leave the TV on standby
20. 20.🧾 A family uses 50 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
21. 21.Which of these saves electricity? (a) set the AC to 24 °C (b) iron one shirt at a time (c) run fans in empty rooms (d) leave fridge door open
22. 22.🧾 A family uses 150 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
23. 23.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 7 hours. How many watt-hours (Wh) are saved?
24. 24.True or false: to unplug idle chargers saves electricity. (a) True (b) False
25. 25.True or false: to set the AC to 24 °C wastes electricity. (a) True (b) False
26. 26.True or false: to use daylight to read saves electricity. (a) True (b) False
27. 27.💡 Does it save or waste electricity to use daylight to read? (a) wastes electricity (b) saves electricity
28. 28.True or false: to leave fridge door open saves electricity. (a) False (b) True
29. 29.Which of these wastes electricity? (a) leave fridge door open (b) use daylight to read (c) set the AC to 24 °C (d) use LED lamps
30. 30.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 3 hours. How many watt-hours (Wh) are saved?
31. 31.Which of these saves electricity? (a) run fans in empty rooms (b) leave fridge door open (c) use LED lamps (d) use old filament bulbs
32. 32.True or false: to leave the TV on standby wastes electricity. (a) False (b) True
33. 33.🔍 Which is the odd one out? (a) leave the TV on standby (b) use LED lamps (c) use daylight to read (d) close the fridge quickly
34. 34.🧾 A 100 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
35. 35.🧾 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?
36. 36.True or false: to switch off empty rooms wastes electricity. (a) False (b) True
37. 37.🧾 A 1500 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
38. 38.🔍 Which is the odd one out? (a) run fans in empty rooms (b) use old filament bulbs (c) unplug idle chargers (d) iron one shirt at a time
39. 39.🧾 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?
40. 40.💡 Does it save or waste electricity to set the AC to 24 °C? (a) saves electricity (b) wastes electricity

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