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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 622 · 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 current of 2 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  2. 2.🧮 Resistors of 22 Ω, 470 Ω and 330 Ω are joined in series. What is the total resistance (in ohms)?
  3. 3.True or false: the voltmeter measures voltage. (a) True (b) False
  4. 4.True or false: on an LED, the round-side leg is the cathode (−). (a) True (b) False
  5. 5.Which of these is measured in volts (V)? (a) how much a part resists (b) energy used each second (c) current (d) voltage
  6. 6.What does a buzzer do? (a) blows if current is high (b) is a resistance knob (c) senses how hot it is (d) makes a beeping sound
  7. 7.⚡ A 27 W device works on 9 V. What current does it take (in amperes)? =
  8. 8.📏 How many milliamperes (mA) is 1.48 A?
  9. 9.⚡ Power tells us … (a) the colour of light (b) the length of a wire (c) the size of a cell (d) energy used each second
  10. 10.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) gets bigger (c) gets smaller (d) stays the same
  11. 11.🧮 Resistors of 33 Ω, 330 Ω, 100 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
  12. 12.True or false: to iron one shirt at a time wastes electricity. (a) False (b) True
  13. 13.🔺 A 3.3 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  14. 14.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = V ÷ I (c) R = V × I (d) R = I ÷ V
  15. 15.🔺 A current of 0.25 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  16. 16.⚡ A device works on 1.5 V and takes 1.5 A. What is its power (in watts)? =
  17. 17.🔺 A current of 20 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
  18. 18.🧮 Resistors of 470 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?
  19. 19.True or false: an LED glows using little power. (a) True (b) False
  20. 20.🔺 A current of 0.5 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  21. 21.🔺 A 22.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  22. 22.⚡ A device works on 9 V and takes 0.2 A. What is its power (in watts)? =
  23. 23.🔺 A current of 50 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  24. 24.🧮 Two equal 1000 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  25. 25.🧮 Three equal 300 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  26. 26.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  27. 27.🔺 In the V-I-R triangle, how do we find V? (a) V = I × R (b) V = R ÷ I (c) V = I + R (d) V = I ÷ R
  28. 28.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) smaller (c) bigger (d) stay the same
  29. 29.What does a buzzer do? (a) is a resistance knob (b) boosts a small signal (c) beeps for an alarm (d) has coloured bands
  30. 30.🔺 A current of 2.5 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  31. 31.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 760 Ω resistor? (a) violet-blue-black (b) violet-blue-red (c) violet-blue-brown (d) blue-violet-brown
  32. 32.🧮 A 3.75 V battery is joined to 5 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
  33. 33.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
  34. 34.🔺 An 8.25 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  35. 35.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
  36. 36.💡 An LED is joined to a 6 V battery through a 470 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) may burn out (b) does not light (c) lights up
  37. 37.📏 How many milliamperes (mA) is 0.09 A?
  38. 38.🧮 A 47 Ω resistor is joined in series with two equal 220 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  39. 39.⚡ A 7.5 W device works on 5 V. What current does it take (in amperes)? =
  40. 40.True or false: how much a part resists is measured in volts (V). (a) True (b) False

Answer key

  1. 6
  2. 822
  3. True
  4. False
  5. voltage
  6. makes a beeping sound
  7. 3
  8. 1480
  9. energy used each second
  10. gets smaller
  11. 473
  12. True
  13. 10
  14. R = V ÷ I
  15. 5
  16. 2.25
  17. 4.4
  18. 620
  19. True
  20. 1.5
  21. 1.5
  22. 1.8
  23. 20
  24. 500
  25. 100
  26. anode (+)
  27. V = I × R
  28. bigger
  29. beeps for an alarm
  30. 20
  31. violet-blue-brown
  32. 0.25
  33. voltmeter
  34. 25
  35. 459
  36. lights up
  37. 90
  38. 157
  39. 1.5
  40. False

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