Electronics Worksheet: Electricity Units

Electronics lesson 19: Electricity units and saving power · Set 20 · 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 family uses 190 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
2. 2.Which of these wastes electricity? (a) use old filament bulbs (b) unplug idle chargers (c) use daylight to read (d) use LED lamps
3. 3.Which of these wastes electricity? (a) close the fridge quickly (b) use LED lamps (c) iron one shirt at a time (d) set the AC to 24 °C
4. 4.🧾 A 250 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
5. 5.🧾 A 500 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
6. 6.🧾 A 1000 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
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 7 hours. How many watt-hours (Wh) are saved?
8. 8.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
9. 9.Which of these saves electricity? (a) unplug idle chargers (b) iron one shirt at a time (c) use old filament bulbs (d) leave fridge door open
10. 10.💡 Does it save or waste electricity to leave fridge door open? (a) wastes electricity (b) saves electricity
11. 11.🧾 A family uses 100 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
12. 12.🧾 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?
13. 13.🔍 Which is the odd one out? (a) run fans in empty rooms (b) use daylight to read (c) leave the TV on standby (d) use old filament bulbs
14. 14.True or false: to iron one shirt at a time saves electricity. (a) False (b) True
15. 15.🔍 Which is the odd one out? (a) leave fridge door open (b) unplug idle chargers (c) use old filament bulbs (d) leave the TV on standby
16. 16.True or false: to use old filament bulbs saves electricity. (a) False (b) True
17. 17.🧾 A 50 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
18. 18.💡 Does it save or waste electricity to use daylight to read? (a) saves electricity (b) wastes electricity
19. 19.🧾 One “unit” on an electricity bill is … (a) 1 kilowatt-hour (kWh) (b) 1 watt (c) 1 ampere (d) 1 volt
20. 20.🧾 A family uses 60 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
21. 21.💡 Does it save or waste electricity to iron one shirt at a time? (a) saves electricity (b) wastes electricity
22. 22.🧾 A family uses 80 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
23. 23.🧾 Which lamp gives the same light for the least power? (a) a candle (b) an oil lamp (c) an LED lamp (d) a filament bulb
24. 24.🔍 Which is the odd one out? (a) use daylight to read (b) use old filament bulbs (c) unplug idle chargers (d) set the AC to 24 °C
25. 25.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
26. 26.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
27. 27.🔍 Which is the odd one out? (a) use old filament bulbs (b) iron one shirt at a time (c) switch off empty rooms (d) leave the TV on standby
28. 28.💡 Does it save or waste electricity to use LED lamps? (a) saves electricity (b) wastes electricity
29. 29.🧾 A family uses 160 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
30. 30.🔍 Which is the odd one out? (a) use daylight to read (b) unplug idle chargers (c) switch off empty rooms (d) leave fridge door open
31. 31.💡 Does it save or waste electricity to leave the TV on standby? (a) saves electricity (b) wastes electricity
32. 32.🧾 A 200 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
33. 33.True or false: to set the AC to 24 °C wastes electricity. (a) False (b) True
34. 34.🔍 Which is the odd one out? (a) run fans in empty rooms (b) iron one shirt at a time (c) use old filament bulbs (d) set the AC to 24 °C
35. 35.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 6 hours. How many watt-hours (Wh) are saved?
36. 36.💡 Does it save or waste electricity to run fans in empty rooms? (a) saves electricity (b) wastes electricity
37. 37.💡 Does it save or waste electricity to close the fridge quickly? (a) wastes electricity (b) saves electricity
38. 38.🧾 A 250 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
39. 39.Which of these saves electricity? (a) use LED lamps (b) leave fridge door open (c) leave the TV on standby (d) iron one shirt at a time
40. 40.🔍 Which is the odd one out? (a) unplug idle chargers (b) close the fridge quickly (c) run fans in empty rooms (d) use daylight to read

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