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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 920 · 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.

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  1. 1.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 6400 Ω resistor? (a) blue-yellow-brown (b) blue-yellow-orange (c) yellow-blue-red (d) blue-yellow-red
  2. 2.True or false: to use daylight to read saves electricity. (a) True (b) False
  3. 3.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 9400 Ω resistor? (a) white-yellow-orange (b) white-yellow-red (c) white-yellow-brown (d) yellow-white-red
  4. 4.True or false: a buzzer lets current go one way. (a) False (b) True
  5. 5.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
  6. 6.⚡ An 18 W device works on 6 V. What current does it take (in amperes)? =
  7. 7.Which of these saves electricity? (a) run fans in empty rooms (b) leave the TV on standby (c) switch off empty rooms (d) leave fridge door open
  8. 8.🧮 Two equal 1000 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  9. 9.🧩 Which component is a resistance knob? (a) LED (b) buzzer (c) capacitor (d) potentiometer
  10. 10.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 0 % (c) 50 % (d) 5 %
  11. 11.🔺 A current of 25 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  12. 12.🌈 In the resistor colour code, which number does violet stand for?
  13. 13.🔍 Which is the odd one out? (a) iron one shirt at a time (b) set the AC to 24 °C (c) use old filament bulbs (d) run fans in empty rooms
  14. 14.🔺 A current of 40 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
  15. 15.🧮 A 47 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)?
  16. 16.True or false: a motor makes things spin. (a) True (b) False
  17. 17.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V + I (d) P = V × I
  18. 18.🧩 Which part changes electrical energy into sound? (a) a buzzer (b) a diode (c) a capacitor (d) a resistor
  19. 19.🔺 A 5.5 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  20. 20.🌈 A resistor has the colour bands blue, yellow, black. What is its value (in ohms)?
  21. 21.⚡ A device works on 3 V and takes 0.1 A. What is its power (in watts)? =
  22. 22.🌈 A resistor has the colour bands green, grey, orange. What is its value (in ohms)?
  23. 23.🧩 Which component lets current go one way? (a) diode (b) buzzer (c) motor (d) LDR
  24. 24.🔺 A current of 0.1 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  25. 25.🌈 A resistor has the colour bands white, green, black. What is its value (in ohms)?
  26. 26.🧩 A capacitor in a circuit can … (a) measure heat (b) make light (c) spin a wheel (d) store charge briefly
  27. 27.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 2 hours. How many watt-hours (Wh) are saved?
  28. 28.🔺 A current of 0.2 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  29. 29.🔺 A current of 0.5 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  30. 30.📏 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
  31. 31.🔺 A current of 20 mA flows when 9.4 V is joined across a resistor. What is its resistance (in ohms)?
  32. 32.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  33. 33.True or false: on an LED, the shorter leg is the anode (+). (a) False (b) True
  34. 34.Which of these is measured in volts (V)? (a) energy used each second (b) the push of a cell (c) current (d) how much a part resists
  35. 35.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  36. 36.💡 Does it save or waste electricity to leave fridge door open? (a) saves electricity (b) wastes electricity
  37. 37.🔺 A 3 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
  38. 38.⚡ A 12 W device works on 12 V. What current does it take (in amperes)? =
  39. 39.📏 Which unit measures power? (a) ohm (Ω) (b) volt (V) (c) watt (W) (d) ampere (A)
  40. 40.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 89000 Ω resistor? (a) white-grey-orange (b) grey-white-orange (c) grey-white-yellow (d) grey-white-red

Answer key

  1. blue-yellow-red
  2. True
  3. white-yellow-red
  4. False
  5. 230
  6. 3
  7. switch off empty rooms
  8. 500
  9. potentiometer
  10. 5 %
  11. 5
  12. 7
  13. set the AC to 24 °C
  14. 13.2
  15. 57
  16. True
  17. P = V × I
  18. a buzzer
  19. 25
  20. 64
  21. 0.3
  22. 58000
  23. diode
  24. 0.5
  25. 95
  26. store charge briefly
  27. 102
  28. 1.2
  29. 7.5
  30. a narrow pipe
  31. 470
  32. cathode (−)
  33. False
  34. the push of a cell
  35. 10
  36. wastes electricity
  37. 10
  38. 1
  39. watt (W)
  40. grey-white-orange

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