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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 755 · 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.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) stay the same (c) zero (d) bigger
  2. 2.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V × I (c) P = V + I (d) P = V ÷ I
  3. 3.🔺 A current of 2.5 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  4. 4.🔺 A 2.2 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  5. 5.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  6. 6.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to a 5 V supply. What current flows (in mA)?
  7. 7.🧩 A capacitor in a circuit can … (a) store charge briefly (b) spin a wheel (c) make light (d) measure heat
  8. 8.🔺 A current of 1.5 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  9. 9.🔺 A current of 0.5 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  10. 10.🔺 A 0.75 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  11. 11.🧩 Which component senses how bright it is? (a) motor (b) buzzer (c) LDR (d) capacitor
  12. 12.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  13. 13.True or false: to iron one shirt at a time saves electricity. (a) True (b) False
  14. 14.🌈 A resistor has the colour bands yellow, brown, yellow. What is its value in kilo-ohms (kΩ)? =
  15. 15.🌈 A resistor has the colour bands grey, violet, orange. What is its value in kilo-ohms (kΩ)? =
  16. 16.📏 Voltmeter or ammeter: which one measures current? (a) ammeter (b) voltmeter
  17. 17.🔺 A current of 25 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
  18. 18.🧩 Which component makes a beeping sound? (a) LDR (b) buzzer (c) potentiometer (d) motor
  19. 19.📏 Voltmeter or ammeter: which one measures voltage? (a) voltmeter (b) ammeter
  20. 20.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets smaller (b) stays the same (c) gets bigger (d) becomes zero
  21. 21.True or false: an LED makes a beeping sound. (a) False (b) True
  22. 22.🔍 Which is the odd one out? (a) iron one shirt at a time (b) use old filament bulbs (c) leave the TV on standby (d) switch off empty rooms
  23. 23.🔺 A current of 0.2 A flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
  24. 24.📏 Which unit measures current? (a) ohm (Ω) (b) volt (V) (c) watt (W) (d) ampere (A)
  25. 25.🌈 In the resistor colour code, which number does orange stand for?
  26. 26.🌈 A resistor has the colour bands violet, brown, black. What is its value (in ohms)?
  27. 27.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = V ÷ R (c) I = V + R (d) I = R ÷ V
  28. 28.🧩 Which part changes electrical energy into movement? (a) an LED (b) a fuse (c) a motor (d) a resistor
  29. 29.🧮 A 15 V battery is joined to 3 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
  30. 30.📏 How many amperes (A) is 1180 mA? =
  31. 31.🔺 A current of 50 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  32. 32.🔺 A current of 0.1 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  33. 33.🧮 A 0.8 V battery is joined to 5 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
  34. 34.🧮 A 1.5 V battery is joined to 12 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
  35. 35.True or false: the flow of charge is measured in ohms (Ω). (a) True (b) False
  36. 36.⚡ Power tells us … (a) the colour of light (b) energy used each second (c) the size of a cell (d) the length of a wire
  37. 37.What does a motor do? (a) is a resistance knob (b) has coloured bands (c) makes things spin (d) makes a beeping sound
  38. 38.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 5 % (c) 25 % (d) 50 %
  39. 39.⚡ A device works on 6 V and takes 0.25 A. What is its power (in watts)? =
  40. 40.🔺 An 8 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =

Answer key

  1. bigger
  2. P = V × I
  3. 15
  4. 10
  5. anode (+)
  6. 10
  7. store charge briefly
  8. 12
  9. 1.5
  10. 0.25
  11. LDR
  12. cathode (−)
  13. False
  14. 410
  15. 87
  16. ammeter
  17. 5.5
  18. buzzer
  19. voltmeter
  20. gets smaller
  21. False
  22. switch off empty rooms
  23. 5
  24. ampere (A)
  25. 3
  26. 71
  27. I = V ÷ R
  28. a motor
  29. 1
  30. 1.18
  31. 20
  32. 0.2
  33. 0.1
  34. 0.1
  35. False
  36. energy used each second
  37. makes things spin
  38. 5 %
  39. 1.5
  40. 1

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