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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 933 · 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 gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 0 % (c) 25 % (d) 5 %
  2. 2.True or false: an LED blows if current is high. (a) False (b) True
  3. 3.⚡ A device works on 3 V and takes 3 A. What is its power (in watts)? =
  4. 4.True or false: a motor senses how hot it is. (a) False (b) True
  5. 5.🔺 A 10 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  6. 6.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 8400 Ω resistor? (a) grey-yellow-red (b) grey-yellow-brown (c) grey-yellow-orange (d) yellow-grey-red
  7. 7.⚡ A 1.5 W device works on 1.5 V. What current does it take (in amperes)? =
  8. 8.🔺 A current of 2.5 A flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
  9. 9.🔺 A current of 50 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
  10. 10.🧮 Two equal 50 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  11. 11.🔺 A 50 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  12. 12.Which of these is measured in amperes (A)? (a) energy used each second (b) resistance (c) how much a part resists (d) current
  13. 13.📏 How many amperes (A) is 520 mA? =
  14. 14.⚡ A device works on 24 V and takes 0.25 A. What is its power (in watts)? =
  15. 15.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
  16. 16.True or false: a motor smooths a wobbly supply. (a) False (b) True
  17. 17.🧮 A 16 V battery is joined to 12 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
  18. 18.🌈 A resistor has the colour bands green, yellow, orange. What is its value (in ohms)?
  19. 19.⚡ Power tells us … (a) the size of a cell (b) the length of a wire (c) energy used each second (d) the colour of light
  20. 20.🔺 A 4 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  21. 21.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
  22. 22.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) stays the same (c) gets smaller (d) becomes zero
  23. 23.📏 In the water-pipe picture of a circuit, current is like … (a) the flow of water (b) a narrow pipe (c) the pipe colour (d) the water pressure
  24. 24.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) a candle (c) an LED lamp (d) a filament bulb
  25. 25.💡 Does it save or waste electricity to unplug idle chargers? (a) wastes electricity (b) saves electricity
  26. 26.🔍 Which is the odd one out? (a) iron one shirt at a time (b) run fans in empty rooms (c) leave fridge door open (d) set the AC to 24 °C
  27. 27.💡 What does LED stand for? (a) large electric dial (b) light energy dial (c) low energy device (d) light-emitting diode
  28. 28.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) smaller (c) zero (d) stay the same
  29. 29.🧩 Which component has coloured bands? (a) fuse (b) resistor (c) LDR (d) potentiometer
  30. 30.🔺 A current of 1.5 A flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
  31. 31.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 100 Ω resistor? (a) brown-black-black (b) red-brown-brown (c) brown-black-brown (d) brown-black-red
  32. 32.🔺 A current of 0.2 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  33. 33.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 390 Ω resistor? (a) white-orange-brown (b) orange-white-black (c) orange-white-brown (d) orange-white-red
  34. 34.🔍 Which is the odd one out? (a) use daylight to read (b) switch off empty rooms (c) run fans in empty rooms (d) use LED lamps
  35. 35.🔺 A current of 0.2 A flows when 1.6 V is joined across a resistor. What is its resistance (in ohms)?
  36. 36.True or false: a resistor limits the current. (a) False (b) True
  37. 37.🔺 A 9 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  38. 38.Which of these saves electricity? (a) leave the TV on standby (b) use old filament bulbs (c) leave fridge door open (d) use LED lamps
  39. 39.🧮 A 1.6 V battery is joined to 4 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
  40. 40.📏 Which unit measures how much a part resists? (a) watt (W) (b) ampere (A) (c) volt (V) (d) ohm (Ω)

Answer key

  1. 5 %
  2. False
  3. 9
  4. False
  5. 40
  6. grey-yellow-red
  7. 1
  8. 8
  9. 23.5
  10. 25
  11. 2.5
  12. current
  13. 0.52
  14. 6
  15. 115
  16. False
  17. 1
  18. 54000
  19. energy used each second
  20. 0.2
  21. 230
  22. gets smaller
  23. the flow of water
  24. an LED lamp
  25. saves electricity
  26. set the AC to 24 °C
  27. light-emitting diode
  28. bigger
  29. resistor
  30. 8
  31. brown-black-brown
  32. 3
  33. orange-white-brown
  34. run fans in empty rooms
  35. 8
  36. True
  37. 3
  38. use LED lamps
  39. 0.1
  40. ohm (Ω)

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