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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 603 · 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 part changes electrical energy into sound? (a) a diode (b) a capacitor (c) a resistor (d) a buzzer
  2. 2.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) more than either one (c) always zero (d) their sum
  3. 3.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 5 % (c) 0 % (d) 25 %
  4. 4.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V × I (c) P = I ÷ V (d) P = V + I
  5. 5.🧮 Two equal 330 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  6. 6.🧮 Three equal 30 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  7. 7.📏 Which unit measures voltage? (a) ampere (A) (b) volt (V) (c) ohm (Ω) (d) watt (W)
  8. 8.🌈 In the resistor colour code, which number does grey stand for?
  9. 9.🧩 Which component makes a beeping sound? (a) buzzer (b) LDR (c) transistor (d) potentiometer
  10. 10.📏 In the water-pipe picture of a circuit, current is like … (a) a narrow pipe (b) the flow of water (c) the pipe colour (d) the water pressure
  11. 11.True or false: an LED glows using little power. (a) True (b) False
  12. 12.📏 How many milliamperes (mA) is 0.85 A?
  13. 13.📏 How many kilowatts (kW) is 350 W? =
  14. 14.⚡ A device works on 5 V and takes 2 A. What is its power (in watts)? =
  15. 15.True or false: a motor turns a fan or wheels. (a) True (b) False
  16. 16.🔺 A current of 0.5 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  17. 17.🔺 A current of 10 mA flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
  18. 18.🔺 A 4 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  19. 19.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) smaller (c) bigger (d) stay the same
  20. 20.🔺 A current of 10 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
  21. 21.📏 Voltmeter or ammeter: which one measures current? (a) ammeter (b) voltmeter
  22. 22.True or false: the ammeter is joined across a part. (a) True (b) False
  23. 23.🌈 Which band is read first on a resistor? (a) the widest gap (b) the gold band (c) the one nearest an end (d) any band
  24. 24.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 200 Ω resistor? (a) red-black-red (b) red-black-black (c) orange-red-brown (d) red-black-brown
  25. 25.🔺 A current of 50 mA flows when 23.5 V is joined across a resistor. What is its resistance (in ohms)?
  26. 26.🌈 In the resistor colour code, which number does violet stand for?
  27. 27.What does a capacitor do? (a) has coloured bands (b) blows if current is high (c) smooths a wobbly supply (d) makes a beeping sound
  28. 28.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) True (b) False
  29. 29.True or false: to run fans in empty rooms wastes electricity. (a) False (b) True
  30. 30.🧾 A 500 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
  31. 31.🔺 A current of 3 A flows when 60 V is joined across a resistor. What is its resistance (in ohms)?
  32. 32.🔺 A current of 0.2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  33. 33.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  34. 34.🌈 A resistor has the colour bands blue, grey, orange. What is its value in kilo-ohms (kΩ)? =
  35. 35.🧩 Which component stores a little charge? (a) capacitor (b) motor (c) LED (d) fuse
  36. 36.⚡ A 3 W device works on 12 V. What current does it take (in amperes)? =
  37. 37.🌈 A resistor has the colour bands red, blue, orange. What is its value (in ohms)?
  38. 38.True or false: voltage is measured in watts (W). (a) False (b) True
  39. 39.⚡ A device works on 6 V and takes 0.25 A. What is its power (in watts)? =
  40. 40.True or false: a diode makes a beeping sound. (a) True (b) False

Answer key

  1. a buzzer
  2. less than either one
  3. 5 %
  4. P = V × I
  5. 165
  6. 10
  7. volt (V)
  8. 8
  9. buzzer
  10. the flow of water
  11. True
  12. 850
  13. 0.35
  14. 10
  15. True
  16. 2
  17. 150
  18. 1
  19. bigger
  20. 3
  21. ammeter
  22. False
  23. the one nearest an end
  24. red-black-brown
  25. 470
  26. 7
  27. smooths a wobbly supply
  28. True
  29. True
  30. 5
  31. 20
  32. 4
  33. anode (+)
  34. 68
  35. capacitor
  36. 0.25
  37. 26000
  38. False
  39. 1.5
  40. False

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