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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 523 · 40 questions
TalentJR

Remember (Find the topic, use the formula): Find the topic and the formula: V = I × R, I = V ÷ R, R = V ÷ I, P = V × I, units = W × h ÷ 1000. Change mA to A and kΩ to Ω before using a formula. Check: put your answer back into the formula.

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  1. 1.🧾 A family uses 100 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  2. 2.Which of these is measured in ohms (Ω)? (a) the flow of charge (b) voltage (c) the push of a cell (d) how much a part resists
  3. 3.🔺 A current of 40 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  4. 4.⚡ A 6 W device works on 12 V. What current does it take (in amperes)? =
  5. 5.Which of these saves electricity? (a) use LED lamps (b) leave fridge door open (c) use old filament bulbs (d) run fans in empty rooms
  6. 6.True or false: an LED senses how bright it is. (a) True (b) False
  7. 7.🌈 A resistor has the colour bands green, red, orange. What is its value in kilo-ohms (kΩ)? =
  8. 8.⚡ A 27 W device works on 9 V. What current does it take (in amperes)? =
  9. 9.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) bigger (c) stay the same (d) smaller
  10. 10.🧮 Five equal 500 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  11. 11.🧩 A capacitor in a circuit can … (a) store charge briefly (b) measure heat (c) make light (d) spin a wheel
  12. 12.🌈 A resistor has the colour bands blue, blue, orange. What is its value (in ohms)?
  13. 13.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
  14. 14.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 25 % (c) 5 % (d) 0 %
  15. 15.🧮 Resistors of 220 Ω and 100 Ω are joined in series. What is the total resistance (in ohms)?
  16. 16.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = V ÷ R (c) I = R ÷ V (d) I = V + R
  17. 17.🔺 A current of 40 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  18. 18.True or false: energy used each second is measured in amperes (A). (a) True (b) False
  19. 19.🔺 A current of 50 mA flows when 7.5 V is joined across a resistor. What is its resistance (in ohms)?
  20. 20.🌈 In the resistor colour code, which number does grey stand for?
  21. 21.🔺 In the V-I-R triangle, how do we find R? (a) R = V ÷ I (b) R = I ÷ V (c) R = V × I (d) R = V + I
  22. 22.What does a motor do? (a) stores a little charge (b) senses how bright it is (c) has coloured bands (d) turns a fan or wheels
  23. 23.True or false: to unplug idle chargers saves electricity. (a) False (b) True
  24. 24.🔺 A current of 50 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
  25. 25.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water tank lid (b) the tap handle (c) the water pressure (d) the pipe colour
  26. 26.📏 How many ohms (Ω) is 7.5 kΩ?
  27. 27.💡 An LED is joined to a 3 V battery through a 330 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) lights up (c) may burn out
  28. 28.🌈 A resistor has the colour bands brown, red, yellow. What is its value in kilo-ohms (kΩ)? =
  29. 29.🔍 Which is the odd one out? (a) leave fridge door open (b) leave the TV on standby (c) use old filament bulbs (d) use daylight to read
  30. 30.📏 How many milliamperes (mA) make 1 ampere? (a) 100 (b) 10 (c) 60 (d) 1000
  31. 31.🧩 Which part changes electrical energy into movement? (a) a resistor (b) a fuse (c) a motor (d) an LED
  32. 32.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 10 hours. How many watt-hours (Wh) are saved?
  33. 33.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  34. 34.🔺 A current of 25 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
  35. 35.🧮 A 470 Ω resistor is joined in series with two equal 10 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  36. 36.🔺 A current of 2 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  37. 37.⚡ A device works on 12 V and takes 3 A. What is its power (in watts)? =
  38. 38.🔺 A 1.5 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  39. 39.⚡ A 4.5 W device works on 1.5 V. What current does it take (in amperes)? =
  40. 40.🔺 A current of 0.25 A flows when 1.25 V is joined across a resistor. What is its resistance (in ohms)?

Answer key

  1. 900
  2. how much a part resists
  3. 16
  4. 0.5
  5. use LED lamps
  6. False
  7. 52
  8. 3
  9. bigger
  10. 100
  11. store charge briefly
  12. 66000
  13. saves electricity
  14. 5 %
  15. 320
  16. I = V ÷ R
  17. 8
  18. False
  19. 150
  20. 8
  21. R = V ÷ I
  22. turns a fan or wheels
  23. True
  24. 15
  25. the water pressure
  26. 7500
  27. lights up
  28. 120
  29. use daylight to read
  30. 1000
  31. a motor
  32. 630
  33. anode (+)
  34. 7.5
  35. 475
  36. 8
  37. 36
  38. 0.5
  39. 3
  40. 5

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