← 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 524 · 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.True or false: an LDR limits the current. (a) True (b) False
  2. 2.🔺 A current of 10 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
  3. 3.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 4 V supply. What current flows (in mA)?
  4. 4.📏 How many milliamperes (mA) is 1.75 A?
  5. 5.📏 How many milliamperes (mA) is 2.04 A?
  6. 6.🔺 A 10 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  7. 7.🧩 Which part changes electrical energy into movement? (a) a motor (b) an LED (c) a fuse (d) a resistor
  8. 8.⚡ A device works on 24 V and takes 0.25 A. What is its power (in watts)? =
  9. 9.🔺 A 20 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  10. 10.📏 Which unit measures voltage? (a) ohm (Ω) (b) ampere (A) (c) watt (W) (d) volt (V)
  11. 11.🧮 Five equal 125 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  12. 12.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V ÷ I (d) P = V × I
  13. 13.🧮 A 1 V battery is joined to 8 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
  14. 14.⚡ Power tells us … (a) the length of a wire (b) the size of a cell (c) the colour of light (d) energy used each second
  15. 15.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V ÷ I (c) R = V + I (d) R = V × I
  16. 16.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 0 % (c) 50 % (d) 5 %
  17. 17.🔺 A current of 0.5 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  18. 18.🔺 A 1 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  19. 19.💡 What happens if an LED is put in backwards? (a) it changes colour (b) it makes a sound (c) it does not light (d) it lights brighter
  20. 20.🔺 A 4 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  21. 21.📏 In the water-pipe picture of a circuit, resistance is like … (a) the water pressure (b) the flow of water (c) a bigger tank (d) a narrow pipe
  22. 22.🌈 In the resistor colour code, which number does yellow stand for?
  23. 23.🔺 A 15 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  24. 24.🔺 A current of 40 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
  25. 25.🧾 A 1500 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  26. 26.🧾 A 100 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
  27. 27.🧩 A capacitor in a circuit can … (a) make light (b) store charge briefly (c) spin a wheel (d) measure heat
  28. 28.📏 Which unit measures energy used each second? (a) watt (W) (b) ampere (A) (c) ohm (Ω) (d) volt (V)
  29. 29.⚡ A device works on 3 V and takes 0.1 A. What is its power (in watts)? =
  30. 30.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  31. 31.📏 How many ohms (Ω) is 8.7 kΩ?
  32. 32.⚡ A 1.5 W device works on 1.5 V. What current does it take (in amperes)? =
  33. 33.🔺 A current of 1.5 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  34. 34.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  35. 35.Which of these saves electricity? (a) leave fridge door open (b) iron one shirt at a time (c) set the AC to 24 °C (d) run fans in empty rooms
  36. 36.📏 How many amperes (A) is 1820 mA? =
  37. 37.📏 How many kilowatts (kW) is 1750 W? =
  38. 38.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 92 Ω resistor? (a) white-red-black (b) white-red-brown (c) red-white-black (d) brown-red-black
  39. 39.🧮 A 150 Ω resistor is joined in series with two equal 330 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  40. 40.🔺 A current of 20 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =

Answer key

  1. False
  2. 3.3
  3. 10
  4. 1750
  5. 2040
  6. 1
  7. a motor
  8. 6
  9. 50
  10. volt (V)
  11. 25
  12. P = V × I
  13. 0.1
  14. energy used each second
  15. R = V ÷ I
  16. 5 %
  17. 3
  18. 0.25
  19. it does not light
  20. 10
  21. a narrow pipe
  22. 4
  23. 3
  24. 12
  25. 3
  26. 0.5
  27. store charge briefly
  28. watt (W)
  29. 0.3
  30. 20
  31. 8700
  32. 1
  33. 4.5
  34. anode (+)
  35. set the AC to 24 °C
  36. 1.82
  37. 1.75
  38. white-red-black
  39. 315
  40. 6

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