← 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 261 · 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 10 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  2. 2.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 volt (c) 1 kilowatt-hour (kWh) (d) 1 ampere
  3. 3.🧮 Resistors of 68 Ω, 22 Ω, 33 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
  4. 4.🧮 Two equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  5. 5.🔺 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
  6. 6.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 50 % (c) 0 % (d) 5 %
  7. 7.🔺 A current of 2 A flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  8. 8.⚡ A 9 W device works on 9 V. What current does it take (in amperes)? =
  9. 9.🔺 A 3.3 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  10. 10.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) stay the same (c) bigger (d) zero
  11. 11.🔺 A 10 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  12. 12.🔺 A 4 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  13. 13.⚡ A 1.2 W device works on 12 V. What current does it take (in amperes)? =
  14. 14.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
  15. 15.🔺 A current of 3 A flows when 60 V is joined across a resistor. What is its resistance (in ohms)?
  16. 16.⚡ A 6 W device works on 12 V. What current does it take (in amperes)? =
  17. 17.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = V × R (c) I = R ÷ V (d) I = V + R
  18. 18.⚡ A 1.5 W device works on 3 V. What current does it take (in amperes)? =
  19. 19.⚡ Power tells us … (a) the length of a wire (b) energy used each second (c) the size of a cell (d) the colour of light
  20. 20.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 2 hours. How many watt-hours (Wh) are saved?
  21. 21.⚡ A 24 W device works on 24 V. What current does it take (in amperes)? =
  22. 22.🔺 A current of 50 mA flows when 11 V is joined across a resistor. What is its resistance (in ohms)?
  23. 23.True or false: the voltmeter is joined in series. (a) False (b) True
  24. 24.True or false: on an LED, the longer leg is the cathode (−). (a) False (b) True
  25. 25.🔺 A current of 50 mA flows when 16.5 V is joined across a resistor. What is its resistance (in ohms)?
  26. 26.🧮 Resistors of 22 Ω, 470 Ω and 330 Ω are joined in series. What is the total resistance (in ohms)?
  27. 27.💡 A blue LED uses 3 V and should get 20 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
  28. 28.🧾 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?
  29. 29.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  30. 30.True or false: the voltmeter measures current. (a) False (b) True
  31. 31.🔺 A current of 0.1 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  32. 32.⚡ Which formula gives electric power? (a) P = V + I (b) P = I ÷ V (c) P = V × I (d) P = V ÷ I
  33. 33.🔺 A current of 0.2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  34. 34.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 4.25 V supply. What current flows (in mA)?
  35. 35.True or false: an LED turns a fan or wheels. (a) False (b) True
  36. 36.Which of these saves electricity? (a) set the AC to 24 °C (b) iron one shirt at a time (c) leave the TV on standby (d) run fans in empty rooms
  37. 37.📏 Voltmeter or ammeter: which one is joined across a part? (a) voltmeter (b) ammeter
  38. 38.🧮 A 150 Ω resistor is joined in series with two equal 220 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  39. 39.💡 A blue LED uses 3 V and should get 25 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
  40. 40.🌈 In the resistor colour code, which number does blue stand for?

Answer key

  1. 0.5
  2. 1 kilowatt-hour (kWh)
  3. 143
  4. 50
  5. V = I × R
  6. 5 %
  7. 5
  8. 1
  9. 10
  10. bigger
  11. 50
  12. 0.2
  13. 0.1
  14. ammeter
  15. 20
  16. 0.5
  17. I = V ÷ R
  18. 0.5
  19. energy used each second
  20. 68
  21. 1
  22. 220
  23. False
  24. False
  25. 330
  26. 822
  27. 450
  28. 34
  29. anode (+)
  30. False
  31. 0.3
  32. P = V × I
  33. 4
  34. 15
  35. False
  36. set the AC to 24 °C
  37. voltmeter
  38. 260
  39. 360
  40. 6

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