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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 14 · 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.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 volt (c) 1 kilowatt-hour (kWh) (d) 1 watt
  2. 2.🔺 A current of 0.25 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  3. 3.🧩 A capacitor in a circuit can … (a) store charge briefly (b) make light (c) measure heat (d) spin a wheel
  4. 4.🔺 A current of 3 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  5. 5.🧮 Two resistors in parallel give a total that is … (a) always zero (b) less than either one (c) more than either one (d) their sum
  6. 6.🧾 A 50 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
  7. 7.🧮 A 20 Ω resistor is joined in series with two equal 200 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  8. 8.🌈 A resistor has the colour bands green, green, orange. What is its value (in ohms)?
  9. 9.True or false: the voltmeter is joined in series. (a) True (b) False
  10. 10.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  11. 11.🔍 Which is the odd one out? (a) switch off empty rooms (b) use daylight to read (c) iron one shirt at a time (d) close the fridge quickly
  12. 12.What does a thermistor do? (a) has coloured bands (b) makes things spin (c) senses how hot it is (d) makes a beeping sound
  13. 13.⚡ A 0.375 W device works on 1.5 V. What current does it take (in amperes)? =
  14. 14.🔺 A current of 40 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  15. 15.True or false: a fuse glows using little power. (a) False (b) True
  16. 16.📏 Which unit measures power? (a) ohm (Ω) (b) ampere (A) (c) volt (V) (d) watt (W)
  17. 17.🔺 A current of 1 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  18. 18.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
  19. 19.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  20. 20.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 28 Ω resistor? (a) orange-grey-black (b) red-grey-brown (c) red-grey-black (d) grey-red-black
  21. 21.🔺 A current of 3 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  22. 22.Which of these wastes electricity? (a) close the fridge quickly (b) use LED lamps (c) switch off empty rooms (d) iron one shirt at a time
  23. 23.⚡ A device works on 1.5 V and takes 0.1 A. What is its power (in watts)? =
  24. 24.🔺 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
  25. 25.🌈 A resistor has the colour bands grey, blue, orange. What is its value (in ohms)?
  26. 26.🔺 A current of 10 mA flows when 2.2 V is joined across a resistor. What is its resistance (in ohms)?
  27. 27.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 410 Ω resistor? (a) brown-yellow-brown (b) yellow-brown-red (c) yellow-brown-brown (d) yellow-brown-black
  28. 28.True or false: on an LED, the round-side leg is the cathode (−). (a) True (b) False
  29. 29.🧮 Resistors of 330 Ω, 10 Ω, 330 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
  30. 30.True or false: resistance is measured in ohms (Ω). (a) False (b) True
  31. 31.📏 How many amperes (A) is 620 mA? =
  32. 32.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  33. 33.🔺 A current of 25 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  34. 34.True or false: current is measured in amperes (A). (a) False (b) True
  35. 35.🔺 A current of 10 mA flows when 3.3 V is joined across a resistor. What is its resistance (in ohms)?
  36. 36.📏 Which unit measures how much a part resists? (a) watt (W) (b) ohm (Ω) (c) ampere (A) (d) volt (V)
  37. 37.🔺 A current of 1 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  38. 38.🌈 A resistor has the colour bands violet, red, black. What is its value (in ohms)?
  39. 39.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 5 hours. How many watt-hours (Wh) are saved?
  40. 40.True or false: on an LED, the longer leg is the cathode (−). (a) True (b) False

Answer key

  1. 1 kilowatt-hour (kWh)
  2. 1.25
  3. store charge briefly
  4. 18
  5. less than either one
  6. 0.5
  7. 120
  8. 55000
  9. False
  10. anode (+)
  11. iron one shirt at a time
  12. senses how hot it is
  13. 0.25
  14. 250
  15. False
  16. watt (W)
  17. 5
  18. 2300
  19. cathode (−)
  20. red-grey-black
  21. 36
  22. iron one shirt at a time
  23. 0.15
  24. R = V ÷ I
  25. 86000
  26. 220
  27. yellow-brown-brown
  28. False
  29. 720
  30. True
  31. 0.62
  32. anode (+)
  33. 10
  34. True
  35. 330
  36. ohm (Ω)
  37. 12
  38. 72
  39. 425
  40. False

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