← 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 259 · 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 current of 0.2 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  2. 2.True or false: on an LED, the shorter leg is the cathode (−). (a) True (b) False
  3. 3.🔺 A current of 0.25 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  4. 4.🔺 A 4 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  5. 5.🔺 A 3.75 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  6. 6.🌈 A resistor has the colour bands white, white, red. What is its value in kilo-ohms (kΩ)? =
  7. 7.🌈 A resistor has the colour bands brown, blue, red. What is its value in kilo-ohms (kΩ)? =
  8. 8.🌈 In the resistor colour code, which number does white stand for?
  9. 9.⚡ A 4.5 W device works on 3 V. What current does it take (in amperes)? =
  10. 10.🔺 A 4 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  11. 11.🔺 A current of 1.5 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  12. 12.🌈 In the resistor colour code, which number does grey stand for?
  13. 13.🧾 A 100 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
  14. 14.📏 In the water-pipe picture of a circuit, voltage is like … (a) the pipe colour (b) the water tank lid (c) the tap handle (d) the water pressure
  15. 15.True or false: an LED glows using little power. (a) True (b) False
  16. 16.🔺 A current of 0.1 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  17. 17.🧮 A 470 Ω resistor is joined in series with two equal 20 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  18. 18.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 25 % (c) 5 % (d) 50 %
  19. 19.🔺 A current of 0.1 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  20. 20.True or false: to unplug idle chargers wastes electricity. (a) False (b) True
  21. 21.🔍 Which is the odd one out? (a) switch off empty rooms (b) leave fridge door open (c) set the AC to 24 °C (d) close the fridge quickly
  22. 22.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 3.5 V supply. What current flows (in mA)?
  23. 23.🔺 A 3 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  24. 24.⚡ A 6 W device works on 6 V. What current does it take (in amperes)? =
  25. 25.🔺 A current of 0.25 A flows when 2.5 V is joined across a resistor. What is its resistance (in ohms)?
  26. 26.💡 Does it save or waste electricity to run fans in empty rooms? (a) wastes electricity (b) saves electricity
  27. 27.⚡ A 1.5 W device works on 6 V. What current does it take (in amperes)? =
  28. 28.⚡ Power tells us … (a) the colour of light (b) the size of a cell (c) energy used each second (d) the length of a wire
  29. 29.🧮 Resistors of 20 Ω and 22 Ω are joined in series. What is the total resistance (in ohms)?
  30. 30.🧮 A 22 Ω resistor is joined in series with two equal 1000 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  31. 31.🔺 A current of 40 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  32. 32.True or false: a resistor stores a little charge. (a) True (b) False
  33. 33.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
  34. 34.🔺 A 6 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  35. 35.True or false: the push of a cell is measured in amperes (A). (a) False (b) True
  36. 36.🌈 Which band is read first on a resistor? (a) the one nearest an end (b) the widest gap (c) any band (d) the gold band
  37. 37.🌈 In the resistor colour code, which number does black stand for?
  38. 38.💡 What happens if an LED is put in backwards? (a) it lights brighter (b) it changes colour (c) it makes a sound (d) it does not light
  39. 39.🔺 A current of 10 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
  40. 40.True or false: an LED senses how hot it is. (a) False (b) True

Answer key

  1. 15
  2. True
  3. 5
  4. 20
  5. 0.25
  6. 9.9
  7. 1.6
  8. 9
  9. 1.5
  10. 40
  11. 2
  12. 8
  13. 0.8
  14. the water pressure
  15. True
  16. 1.2
  17. 480
  18. 5 %
  19. 0.5
  20. False
  21. leave fridge door open
  22. 10
  23. 20
  24. 1
  25. 10
  26. wastes electricity
  27. 0.25
  28. energy used each second
  29. 42
  30. 522
  31. 6
  32. False
  33. 115
  34. 2
  35. False
  36. the one nearest an end
  37. 0
  38. it does not light
  39. 3
  40. False

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