← Part 2 test: components and Ohm’s law lesson New set →

Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 116 · 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.🌈 A resistor has the colour bands yellow, brown, black. What is its value (in ohms)?
  2. 2.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 80 Ω resistor? (a) white-grey-black (b) white-black-black (c) grey-black-black (d) grey-black-brown
  3. 3.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V × I (c) P = V + I (d) P = V ÷ I
  4. 4.⚡ A device works on 24 V and takes 0.2 A. What is its power (in watts)? =
  5. 5.🌈 A resistor has the colour bands green, blue, black. What is its value (in ohms)?
  6. 6.💡 What happens if an LED is put in backwards? (a) it makes a sound (b) it does not light (c) it changes colour (d) it lights brighter
  7. 7.🔺 A current of 50 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
  8. 8.💡 Does it save or waste electricity to use LED lamps? (a) saves electricity (b) wastes electricity
  9. 9.🔺 A current of 0.1 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  10. 10.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 400 Ω resistor? (a) yellow-black-red (b) yellow-black-brown (c) yellow-black-black (d) green-yellow-brown
  11. 11.🧩 A capacitor in a circuit can … (a) make light (b) measure heat (c) spin a wheel (d) store charge briefly
  12. 12.⚡ A device works on 1.5 V and takes 2 A. What is its power (in watts)? =
  13. 13.🌈 A resistor has the colour bands red, brown, black. What is its value (in ohms)?
  14. 14.🔺 A current of 40 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
  15. 15.⚡ A 1.5 W device works on 1.5 V. What current does it take (in amperes)? =
  16. 16.🧮 A 1.8 V battery is joined to 4 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
  17. 17.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) a candle (c) an LED lamp (d) a filament bulb
  18. 18.🧮 Two equal 330 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  19. 19.🌈 In the resistor colour code, which number does violet stand for?
  20. 20.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) stay the same (c) bigger (d) smaller
  21. 21.🧮 A 10 Ω resistor is joined in series with two equal 10 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  22. 22.💡 An LED is joined to a 6 V battery through a 330 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) does not light (b) may burn out (c) lights up
  23. 23.🧩 Which part changes electrical energy into movement? (a) a fuse (b) a resistor (c) a motor (d) an LED
  24. 24.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 25 % (c) 5 % (d) 50 %
  25. 25.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  26. 26.📏 Which unit measures the push of a cell? (a) ampere (A) (b) ohm (Ω) (c) volt (V) (d) watt (W)
  27. 27.💡 A blue LED uses 3 V and should get 25 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
  28. 28.🔺 A 16 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  29. 29.🔺 A current of 10 mA flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
  30. 30.🧮 A 2.8 V battery is joined to 8 Ω and 6 Ω resistors in series. What current flows (in amperes)? =
  31. 31.🌈 A resistor has the colour bands violet, black, red. What is its value (in ohms)?
  32. 32.📏 How many ohms (Ω) is 2.7 kΩ?
  33. 33.⚡ A 4.5 W device works on 9 V. What current does it take (in amperes)? =
  34. 34.💡 Why does an LED need a resistor in series? (a) to limit the current (b) to make it brighter (c) to store charge (d) to change its colour
  35. 35.🔺 A 3 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  36. 36.🔺 A 12.5 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
  37. 37.🔺 A current of 3 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  38. 38.⚡ A 1.25 W device works on 5 V. What current does it take (in amperes)? =
  39. 39.⚡ A 1.5 W device works on 3 V. What current does it take (in amperes)? =
  40. 40.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = I ÷ V (c) R = V × I (d) R = V ÷ I

Answer key

  1. 41
  2. grey-black-black
  3. P = V × I
  4. 4.8
  5. 56
  6. it does not light
  7. 12.5
  8. saves electricity
  9. 0.2
  10. yellow-black-brown
  11. store charge briefly
  12. 3
  13. 21
  14. 10
  15. 1
  16. 0.2
  17. an LED lamp
  18. 165
  19. 7
  20. bigger
  21. 15
  22. does not light
  23. a motor
  24. 5 %
  25. anode (+)
  26. volt (V)
  27. 240
  28. 2
  29. 150
  30. 0.2
  31. 7000
  32. 2700
  33. 0.5
  34. to limit the current
  35. 20
  36. 25
  37. 45
  38. 0.25
  39. 0.5
  40. R = V ÷ I

Free electronics lessons, practice and worksheets at talentjr.in/electronics-for-kids