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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 231 · 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 use daylight to read? (a) wastes electricity (b) saves electricity
  2. 2.🌈 In the resistor colour code, which number does brown stand for?
  3. 3.📏 How many kilo-ohms (kΩ) is 2900 Ω? =
  4. 4.🌈 A resistor has the colour bands blue, violet, orange. What is its value in kilo-ohms (kΩ)? =
  5. 5.🧩 A capacitor in a circuit can … (a) measure heat (b) store charge briefly (c) spin a wheel (d) make light
  6. 6.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) a candle (c) a filament bulb (d) an LED lamp
  7. 7.🧮 A 22 V battery is joined to 12 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
  8. 8.True or false: a resistor limits the current. (a) True (b) False
  9. 9.⚡ A 2.25 W device works on 9 V. What current does it take (in amperes)? =
  10. 10.🧾 A 1500 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
  11. 11.🧾 A 50 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
  12. 12.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V × I (c) P = V + I (d) P = I ÷ V
  13. 13.🔺 A current of 25 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  14. 14.🧮 Resistors of 20 Ω, 20 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
  15. 15.⚡ A 0.3 W device works on 3 V. What current does it take (in amperes)? =
  16. 16.🔺 A 4.7 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
  17. 17.True or false: a diode makes a beeping sound. (a) True (b) False
  18. 18.📏 How many kilo-ohms (kΩ) is 6400 Ω? =
  19. 19.📏 Which unit measures energy used each second? (a) watt (W) (b) ampere (A) (c) volt (V) (d) ohm (Ω)
  20. 20.🔺 A current of 0.1 A flows when 1.2 V is joined across a resistor. What is its resistance (in ohms)?
  21. 21.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  22. 22.🧮 A 10 Ω resistor is joined in series with two equal 40 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  23. 23.🌈 A resistor has the colour bands orange, brown, orange. What is its value in kilo-ohms (kΩ)? =
  24. 24.🔺 A current of 10 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
  25. 25.🌈 A resistor has the colour bands violet, red, orange. What is its value (in ohms)?
  26. 26.🔺 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
  27. 27.🧮 Resistors of 68 Ω and 22 Ω are joined in series. What is the total resistance (in ohms)?
  28. 28.True or false: current is measured in ohms (Ω). (a) False (b) True
  29. 29.True or false: voltage is measured in volts (V). (a) False (b) True
  30. 30.What does a motor do? (a) boosts a small signal (b) lets current go one way (c) turns a fan or wheels (d) senses how hot it is
  31. 31.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
  32. 32.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 1 hour. How many watt-hours (Wh) are saved?
  33. 33.🔺 A current of 0.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  34. 34.True or false: to use LED lamps saves electricity. (a) False (b) True
  35. 35.📏 Which unit measures how much a part resists? (a) volt (V) (b) watt (W) (c) ohm (Ω) (d) ampere (A)
  36. 36.True or false: on an LED, the longer leg is the cathode (−). (a) False (b) True
  37. 37.🌈 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
  38. 38.🔺 A 1.2 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  39. 39.🔺 A 6 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  40. 40.🔺 A 9.4 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?

Answer key

  1. saves electricity
  2. 1
  3. 2.9
  4. 67
  5. store charge briefly
  6. an LED lamp
  7. 1
  8. True
  9. 0.25
  10. 6
  11. 0.2
  12. P = V × I
  13. 3.75
  14. 90
  15. 0.1
  16. 10
  17. False
  18. 6.4
  19. watt (W)
  20. 12
  21. anode (+)
  22. 30
  23. 31
  24. 4.7
  25. 72000
  26. V = I × R
  27. 90
  28. False
  29. True
  30. turns a fan or wheels
  31. 1840
  32. 34
  33. 2.5
  34. True
  35. ohm (Ω)
  36. False
  37. the one nearest an end
  38. 0.2
  39. 1
  40. 20

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