← 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 497 · 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 0.5 A flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
  2. 2.🔺 A current of 20 mA flows when 4.4 V is joined across a resistor. What is its resistance (in ohms)?
  3. 3.🔺 A current of 20 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
  4. 4.💡 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
  5. 5.🌈 A resistor has the colour bands grey, grey, black. What is its value (in ohms)?
  6. 6.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 92 Ω resistor? (a) white-red-black (b) red-white-black (c) white-red-brown (d) brown-red-black
  7. 7.🔺 A current of 0.2 A flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
  8. 8.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) always zero (c) more than either one (d) their sum
  9. 9.True or false: the voltmeter is joined in series. (a) True (b) False
  10. 10.🔺 A 2 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  11. 11.💡 A red LED uses 2 V and should get 25 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
  12. 12.🔺 A 0.4 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  13. 13.True or false: to switch off empty rooms wastes electricity. (a) False (b) True
  14. 14.🧩 Which part changes electrical energy into movement? (a) an LED (b) a motor (c) a resistor (d) a fuse
  15. 15.🔺 A 6 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  16. 16.Which of these is measured in amperes (A)? (a) resistance (b) power (c) energy used each second (d) current
  17. 17.Which of these wastes electricity? (a) unplug idle chargers (b) set the AC to 24 °C (c) switch off empty rooms (d) iron one shirt at a time
  18. 18.🧮 Two equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  19. 19.🧩 A capacitor in a circuit can … (a) spin a wheel (b) measure heat (c) make light (d) store charge briefly
  20. 20.⚡ Power tells us … (a) the length of a wire (b) the colour of light (c) energy used each second (d) the size of a cell
  21. 21.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V + I (c) P = I ÷ V (d) P = V × I
  22. 22.📏 How many milliamperes (mA) make 1 ampere? (a) 60 (b) 10 (c) 1000 (d) 100
  23. 23.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 64 Ω resistor? (a) violet-yellow-black (b) blue-yellow-brown (c) blue-yellow-black (d) yellow-blue-black
  24. 24.🧾 Which lamp gives the same light for the least power? (a) an LED lamp (b) a filament bulb (c) an oil lamp (d) a candle
  25. 25.🔍 Which is the odd one out? (a) use LED lamps (b) set the AC to 24 °C (c) close the fridge quickly (d) leave fridge door open
  26. 26.🧮 Resistors of 150 Ω, 220 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
  27. 27.📏 How many kilo-ohms (kΩ) is 2000 Ω? =
  28. 28.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
  29. 29.🔺 A current of 0.5 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  30. 30.🧾 A 1500 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
  31. 31.📏 How many amperes (A) is 2840 mA? =
  32. 32.🧮 A 2 V battery is joined to 2 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
  33. 33.🔺 A current of 50 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
  34. 34.⚡ A 36 W device works on 24 V. What current does it take (in amperes)? =
  35. 35.⚡ A 0.3 W device works on 3 V. What current does it take (in amperes)? =
  36. 36.💡 Does it save or waste electricity to close the fridge quickly? (a) saves electricity (b) wastes electricity
  37. 37.⚡ A device works on 9 V and takes 0.1 A. What is its power (in watts)? =
  38. 38.🧮 Four equal 400 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  39. 39.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 790 Ω resistor? (a) white-violet-brown (b) violet-white-brown (c) violet-white-red (d) violet-white-black
  40. 40.🧮 Resistors of 150 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?

Answer key

  1. 2
  2. 220
  3. 10
  4. to limit the current
  5. 88
  6. white-red-black
  7. 5
  8. less than either one
  9. False
  10. 20
  11. 120
  12. 0.2
  13. False
  14. a motor
  15. 3
  16. current
  17. iron one shirt at a time
  18. 100
  19. store charge briefly
  20. energy used each second
  21. P = V × I
  22. 1000
  23. blue-yellow-black
  24. an LED lamp
  25. leave fridge door open
  26. 390
  27. 2
  28. 460
  29. 7.5
  30. 6
  31. 2.84
  32. 0.2
  33. 12.5
  34. 1.5
  35. 0.1
  36. saves electricity
  37. 0.9
  38. 100
  39. violet-white-brown
  40. 170

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