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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 521 · 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.💡 Does it save or waste electricity to iron one shirt at a time? (a) saves electricity (b) wastes electricity
  2. 2.🔺 A current of 50 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
  3. 3.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 870 Ω resistor? (a) violet-grey-brown (b) grey-violet-red (c) grey-violet-black (d) grey-violet-brown
  4. 4.🧮 Five equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  5. 5.📏 Which unit measures how much a part resists? (a) watt (W) (b) volt (V) (c) ohm (Ω) (d) ampere (A)
  6. 6.📏 How many kilo-ohms (kΩ) is 1900 Ω? =
  7. 7.🔺 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
  8. 8.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 0 % (c) 50 % (d) 25 %
  9. 9.🧮 Resistors of 22 Ω, 10 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
  10. 10.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) True (b) False
  11. 11.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V × I (c) P = V ÷ I (d) P = V + I
  12. 12.🔺 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
  13. 13.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) their sum (c) always zero (d) less than either one
  14. 14.🧩 Which part changes electrical energy into sound? (a) a capacitor (b) a diode (c) a resistor (d) a buzzer
  15. 15.🔺 A 3 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  16. 16.🧩 A capacitor in a circuit can … (a) measure heat (b) make light (c) spin a wheel (d) store charge briefly
  17. 17.🔺 A current of 1.5 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  18. 18.True or false: a motor has coloured bands. (a) False (b) True
  19. 19.What does a capacitor do? (a) stores a little charge (b) lets current go one way (c) turns a fan or wheels (d) beeps for an alarm
  20. 20.🌈 In the resistor colour code, which number does violet stand for?
  21. 21.True or false: the ammeter measures current. (a) True (b) False
  22. 22.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 4300 Ω resistor? (a) yellow-orange-red (b) orange-yellow-red (c) yellow-orange-orange (d) yellow-orange-brown
  23. 23.Which of these is measured in watts (W)? (a) voltage (b) current (c) energy used each second (d) resistance
  24. 24.🧮 Resistors of 470 Ω, 33 Ω, 10 Ω and 330 Ω are joined in series. What is the total resistance (in ohms)?
  25. 25.Which of these is measured in watts (W)? (a) current (b) power (c) the flow of charge (d) how much a part resists
  26. 26.🌈 Which band is read first on a resistor? (a) the gold band (b) the widest gap (c) the one nearest an end (d) any band
  27. 27.True or false: a thermistor smooths a wobbly supply. (a) True (b) False
  28. 28.🧩 Which component turns a fan or wheels? (a) motor (b) fuse (c) potentiometer (d) resistor
  29. 29.True or false: a diode is a resistance knob. (a) False (b) True
  30. 30.🔺 A current of 2 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  31. 31.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  32. 32.⚡ A device works on 24 V and takes 0.5 A. What is its power (in watts)? =
  33. 33.True or false: to use LED lamps saves electricity. (a) True (b) False
  34. 34.💡 Does it save or waste electricity to unplug idle chargers? (a) wastes electricity (b) saves electricity
  35. 35.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 3 V supply. What current flows (in mA)?
  36. 36.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 61 Ω resistor? (a) brown-blue-black (b) violet-brown-black (c) blue-brown-black (d) blue-brown-brown
  37. 37.🔺 A current of 0.1 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  38. 38.🔺 A current of 2.5 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  39. 39.⚡ A device works on 9 V and takes 0.25 A. What is its power (in watts)? =
  40. 40.🔺 A current of 0.2 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =

Answer key

  1. wastes electricity
  2. 16.5
  3. grey-violet-brown
  4. 20
  5. ohm (Ω)
  6. 1.9
  7. V = I × R
  8. 5 %
  9. 42
  10. True
  11. P = V × I
  12. R = V ÷ I
  13. less than either one
  14. a buzzer
  15. 0.2
  16. store charge briefly
  17. 12
  18. False
  19. stores a little charge
  20. 7
  21. True
  22. yellow-orange-red
  23. energy used each second
  24. 843
  25. power
  26. the one nearest an end
  27. False
  28. motor
  29. False
  30. 8
  31. anode (+)
  32. 12
  33. True
  34. saves electricity
  35. 5
  36. blue-brown-black
  37. 0.4
  38. 20
  39. 2.25
  40. 0.8

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