← 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 941 · 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 1500 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
  2. 2.True or false: on an LED, the shorter leg is the anode (+). (a) False (b) True
  3. 3.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter
  4. 4.⚡ Which formula gives electric power? (a) P = V × I (b) P = I ÷ V (c) P = V ÷ I (d) P = V + I
  5. 5.🧩 Which component turns a fan or wheels? (a) thermistor (b) motor (c) fuse (d) buzzer
  6. 6.🌈 In the resistor colour code, which number does brown stand for?
  7. 7.🔺 A current of 1.5 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  8. 8.🌈 A resistor has the colour bands white, orange, orange. What is its value in kilo-ohms (kΩ)? =
  9. 9.🔺 A 4 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  10. 10.🔺 A current of 2.5 A flows when 50 V is joined across a resistor. What is its resistance (in ohms)?
  11. 11.True or false: to iron one shirt at a time wastes electricity. (a) False (b) True
  12. 12.🧩 Which part changes electrical energy into sound? (a) a resistor (b) a capacitor (c) a buzzer (d) a diode
  13. 13.🔺 A current of 3 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  14. 14.True or false: an LED lets current go one way. (a) True (b) False
  15. 15.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
  16. 16.🔺 A 1 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  17. 17.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V ÷ R (c) I = V + R (d) I = V × R
  18. 18.⚡ A device works on 3 V and takes 0.25 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) cathode (−) (b) anode (+)
  20. 20.🔺 A 16 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  21. 21.Which of these wastes electricity? (a) set the AC to 24 °C (b) use LED lamps (c) close the fridge quickly (d) run fans in empty rooms
  22. 22.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
  23. 23.🔺 A current of 3 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  24. 24.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = I + R (c) V = I × R (d) V = R ÷ I
  25. 25.True or false: on an LED, the leg by the flat edge is the anode (+). (a) True (b) False
  26. 26.🧮 Two resistors in parallel give a total that is … (a) their sum (b) more than either one (c) less than either one (d) always zero
  27. 27.🌈 Which band is read first on a resistor? (a) any band (b) the one nearest an end (c) the widest gap (d) the gold band
  28. 28.What does a fuse do? (a) limits the current (b) beeps for an alarm (c) blows if current is high (d) senses how hot it is
  29. 29.💡 Why does an LED need a resistor in series? (a) to store charge (b) to make it brighter (c) to change its colour (d) to limit the current
  30. 30.⚡ A 4.5 W device works on 3 V. What current does it take (in amperes)? =
  31. 31.🔺 A 10 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  32. 32.🌈 In the resistor colour code, which number does blue stand for?
  33. 33.🧮 Two equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  34. 34.True or false: on an LED, the longer leg is the anode (+). (a) True (b) False
  35. 35.🌈 In the resistor colour code, which number does violet stand for?
  36. 36.🧩 A capacitor in a circuit can … (a) measure heat (b) make light (c) spin a wheel (d) store charge briefly
  37. 37.🔺 A current of 3 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  38. 38.🧮 A 1.2 V battery is joined to 4 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
  39. 39.🔺 A 60 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  40. 40.📏 How many kilo-ohms (kΩ) is 5600 Ω? =

Answer key

  1. 6
  2. False
  3. ammeter
  4. P = V × I
  5. motor
  6. 1
  7. 12
  8. 93
  9. 40
  10. 20
  11. True
  12. a buzzer
  13. 60
  14. False
  15. ammeter
  16. 0.5
  17. I = V ÷ R
  18. 0.75
  19. cathode (−)
  20. 40
  21. run fans in empty rooms
  22. 1840
  23. 36
  24. V = I × R
  25. False
  26. less than either one
  27. the one nearest an end
  28. blows if current is high
  29. to limit the current
  30. 1.5
  31. 25
  32. 6
  33. 100
  34. True
  35. 7
  36. store charge briefly
  37. 45
  38. 0.1
  39. 3
  40. 5.6

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