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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 84 · 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.

NameDateTime takenScore ___ / 40
  1. 1.🔍 Which is the odd one out? (a) use LED lamps (b) iron one shirt at a time (c) use daylight to read (d) switch off empty rooms
  2. 2.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) an LED lamp (c) an oil lamp (d) a candle
  3. 3.🌈 A resistor has the colour bands violet, orange, black. What is its value (in ohms)?
  4. 4.🔺 A current of 2.5 A flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
  5. 5.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) smaller (c) stay the same (d) zero
  6. 6.True or false: to use LED lamps wastes electricity. (a) False (b) True
  7. 7.🔺 A current of 3 A flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
  8. 8.📏 Voltmeter or ammeter: which one measures voltage? (a) voltmeter (b) ammeter
  9. 9.True or false: to iron one shirt at a time wastes electricity. (a) True (b) False
  10. 10.🌈 A resistor has the colour bands green, yellow, red. What is its value (in ohms)?
  11. 11.📏 How many ohms (Ω) is 6.2 kΩ?
  12. 12.💡 A blue LED uses 3 V and should get 20 mA. It runs from a 6 V supply. What resistor (in ohms) is needed in series?
  13. 13.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 5 % (c) 0 % (d) 50 %
  14. 14.🔺 A current of 50 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
  15. 15.⚡ A device works on 9 V and takes 2 A. What is its power (in watts)? =
  16. 16.📏 In the water-pipe picture of a circuit, resistance is like … (a) a bigger tank (b) the water pressure (c) a narrow pipe (d) the flow of water
  17. 17.🌈 A resistor has the colour bands red, brown, black. What is its value (in ohms)?
  18. 18.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water pressure (b) the water tank lid (c) the pipe colour (d) the tap handle
  19. 19.🔺 A current of 40 mA flows when 18.8 V is joined across a resistor. What is its resistance (in ohms)?
  20. 20.Which of these wastes electricity? (a) close the fridge quickly (b) use LED lamps (c) use daylight to read (d) leave fridge door open
  21. 21.⚡ Which formula gives electric power? (a) P = V + I (b) P = V × I (c) P = V ÷ I (d) P = I ÷ V
  22. 22.True or false: to switch off empty rooms wastes electricity. (a) True (b) False
  23. 23.True or false: the ammeter is joined across a part. (a) True (b) False
  24. 24.🧩 Which component boosts a small signal? (a) LED (b) transistor (c) resistor (d) buzzer
  25. 25.🔺 A current of 0.1 A flows when 0.6 V is joined across a resistor. What is its resistance (in ohms)?
  26. 26.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  27. 27.🧮 A 1.8 V battery is joined to 10 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
  28. 28.True or false: a capacitor stores a little charge. (a) True (b) False
  29. 29.What does a transistor do? (a) senses how hot it is (b) makes things spin (c) has coloured bands (d) boosts a small signal
  30. 30.True or false: the voltmeter measures current. (a) False (b) True
  31. 31.🔺 A current of 40 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
  32. 32.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  33. 33.🧮 Resistors of 220 Ω, 20 Ω and 22 Ω are joined in series. What is the total resistance (in ohms)?
  34. 34.🔺 In the V-I-R triangle, how do we find I? (a) I = V + R (b) I = R ÷ V (c) I = V × R (d) I = V ÷ R
  35. 35.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 34 Ω resistor? (a) yellow-orange-black (b) yellow-yellow-black (c) orange-yellow-black (d) orange-yellow-brown
  36. 36.🌈 A resistor has the colour bands grey, red, red. What is its value (in ohms)?
  37. 37.True or false: on an LED, the round-side leg is the anode (+). (a) True (b) False
  38. 38.🧮 Resistors of 33 Ω and 47 Ω are joined in series. What is the total resistance (in ohms)?
  39. 39.💡 A red LED uses 2 V and should get 25 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
  40. 40.True or false: the ammeter measures voltage. (a) True (b) False

Answer key

  1. iron one shirt at a time
  2. an LED lamp
  3. 73
  4. 8
  5. bigger
  6. False
  7. 2
  8. voltmeter
  9. True
  10. 5400
  11. 6200
  12. 150
  13. 5 %
  14. 16.5
  15. 18
  16. a narrow pipe
  17. 21
  18. the water pressure
  19. 470
  20. leave fridge door open
  21. P = V × I
  22. False
  23. False
  24. transistor
  25. 6
  26. cathode (−)
  27. 0.1
  28. True
  29. boosts a small signal
  30. False
  31. 13.2
  32. anode (+)
  33. 262
  34. I = V ÷ R
  35. orange-yellow-black
  36. 8200
  37. True
  38. 80
  39. 400
  40. False

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