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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 735 · 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.True or false: a motor makes things spin. (a) True (b) False
  2. 2.🔺 A current of 2 A flows when 40 V is joined across a resistor. What is its resistance (in ohms)?
  3. 3.🧩 Which component makes things spin? (a) transistor (b) buzzer (c) motor (d) thermistor
  4. 4.🔺 A current of 40 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
  5. 5.True or false: an LDR makes things spin. (a) True (b) False
  6. 6.🌈 Which band is read first on a resistor? (a) the widest gap (b) the gold band (c) the one nearest an end (d) any band
  7. 7.📏 Voltmeter or ammeter: which one is joined across a part? (a) voltmeter (b) ammeter
  8. 8.🌈 A resistor has the colour bands orange, orange, black. What is its value (in ohms)?
  9. 9.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter
  10. 10.💡 An LED is joined to a 9 V battery through a 470 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) lights up (b) may burn out (c) does not light
  11. 11.🧩 Which component boosts a small signal? (a) motor (b) diode (c) transistor (d) potentiometer
  12. 12.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = V ÷ I (c) R = I ÷ V (d) R = V × I
  13. 13.🔺 A current of 40 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
  14. 14.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V ÷ I (d) P = V × I
  15. 15.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  16. 16.True or false: the voltmeter measures voltage. (a) False (b) True
  17. 17.🔺 An 11 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  18. 18.🔺 A current of 0.5 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  19. 19.🧮 A 1.4 V battery is joined to 10 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
  20. 20.🔺 A current of 20 mA flows when 9.4 V is joined across a resistor. What is its resistance (in ohms)?
  21. 21.🧩 Which part changes electrical energy into sound? (a) a diode (b) a capacitor (c) a resistor (d) a buzzer
  22. 22.📏 How many amperes (A) is 2720 mA? =
  23. 23.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  24. 24.🔺 In the V-I-R triangle, how do we find V? (a) V = I × R (b) V = I + R (c) V = R ÷ I (d) V = I ÷ R
  25. 25.🌈 A resistor has the colour bands red, blue, black. What is its value (in ohms)?
  26. 26.🔺 A current of 25 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  27. 27.🔺 A current of 10 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  28. 28.Which of these wastes electricity? (a) switch off empty rooms (b) use daylight to read (c) use old filament bulbs (d) set the AC to 24 °C
  29. 29.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 10 hours. How many watt-hours (Wh) are saved?
  30. 30.🔺 A 37.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  31. 31.🧩 Which part changes electrical energy into movement? (a) an LED (b) a fuse (c) a resistor (d) a motor
  32. 32.True or false: current is measured in ohms (Ω). (a) True (b) False
  33. 33.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 2.75 V supply. What current flows (in mA)?
  34. 34.🔺 A current of 20 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  35. 35.True or false: to use daylight to read saves electricity. (a) True (b) False
  36. 36.⚡ A device works on 3 V and takes 1.5 A. What is its power (in watts)? =
  37. 37.🔺 A current of 10 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
  38. 38.⚡ A 1.5 W device works on 6 V. What current does it take (in amperes)? =
  39. 39.True or false: on an LED, the longer leg is the anode (+). (a) False (b) True
  40. 40.True or false: a capacitor boosts a small signal. (a) True (b) False

Answer key

  1. True
  2. 20
  3. motor
  4. 8.8
  5. False
  6. the one nearest an end
  7. voltmeter
  8. 33
  9. ammeter
  10. does not light
  11. transistor
  12. R = V ÷ I
  13. 20
  14. P = V × I
  15. anode (+)
  16. True
  17. 50
  18. 2
  19. 0.1
  20. 470
  21. a buzzer
  22. 2.72
  23. 20
  24. V = I × R
  25. 26
  26. 5
  27. 2
  28. use old filament bulbs
  29. 850
  30. 2.5
  31. a motor
  32. False
  33. 5
  34. 8
  35. True
  36. 4.5
  37. 5
  38. 0.25
  39. True
  40. False

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