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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 731 · 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.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
  2. 2.🧮 A 330 Ω resistor is joined in series with two equal 50 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  3. 3.⚡ 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
  4. 4.🧮 A 1.6 V battery is joined to 4 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
  5. 5.What does a resistor do? (a) turns a fan or wheels (b) is a resistance knob (c) beeps for an alarm (d) has coloured bands
  6. 6.🧩 Which component stores a little charge? (a) diode (b) buzzer (c) capacitor (d) motor
  7. 7.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) bigger (c) zero (d) smaller
  8. 8.🔺 A current of 10 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
  9. 9.📏 Voltmeter or ammeter: which one measures voltage? (a) voltmeter (b) ammeter
  10. 10.💡 What does LED stand for? (a) light energy dial (b) large electric dial (c) light-emitting diode (d) low energy device
  11. 11.⚡ A device works on 3 V and takes 0.2 A. What is its power (in watts)? =
  12. 12.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
  13. 13.🧮 Two equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  14. 14.🔺 A current of 0.25 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  15. 15.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = V ÷ I (c) R = I ÷ V (d) R = V + I
  16. 16.🔺 A 2.4 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  17. 17.📏 How many ohms (Ω) is 9.2 kΩ?
  18. 18.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 1024 (b) 10 (c) 100 (d) 1000
  19. 19.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 4.25 V supply. What current flows (in mA)?
  20. 20.🧩 Which component turns a fan or wheels? (a) transistor (b) capacitor (c) fuse (d) motor
  21. 21.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  22. 22.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) becomes zero (c) stays the same (d) gets smaller
  23. 23.⚡ A device works on 6 V and takes 1.5 A. What is its power (in watts)? =
  24. 24.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
  25. 25.🧩 Which component makes a beeping sound? (a) thermistor (b) motor (c) buzzer (d) capacitor
  26. 26.🔺 A 10 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  27. 27.🔺 A current of 0.25 A flows when 0.75 V is joined across a resistor. What is its resistance (in ohms)?
  28. 28.🔺 A current of 2 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  29. 29.⚡ A device works on 5 V and takes 0.2 A. What is its power (in watts)? =
  30. 30.True or false: on an LED, the shorter leg is the anode (+). (a) False (b) True
  31. 31.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) False (b) True
  32. 32.📏 How many watts (W) is 2.9 kW?
  33. 33.🧮 A 1.25 V battery is joined to 3 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
  34. 34.🧮 Resistors of 22 Ω, 10 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?
  35. 35.⚡ A 5 W device works on 5 V. What current does it take (in amperes)? =
  36. 36.🧩 Which component blows if current is high? (a) capacitor (b) diode (c) LED (d) fuse
  37. 37.⚡ A device works on 9 V and takes 1.5 A. What is its power (in watts)? =
  38. 38.🧩 A capacitor in a circuit can … (a) measure heat (b) spin a wheel (c) make light (d) store charge briefly
  39. 39.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
  40. 40.🔺 A 15 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =

Answer key

  1. ammeter
  2. 355
  3. energy used each second
  4. 0.1
  5. has coloured bands
  6. capacitor
  7. bigger
  8. 2.5
  9. voltmeter
  10. light-emitting diode
  11. 0.6
  12. 345
  13. 100
  14. 5
  15. R = V ÷ I
  16. 20
  17. 9200
  18. 1000
  19. 15
  20. motor
  21. anode (+)
  22. gets smaller
  23. 9
  24. 200
  25. buzzer
  26. 50
  27. 3
  28. 20
  29. 1
  30. False
  31. True
  32. 2900
  33. 0.25
  34. 182
  35. 1
  36. fuse
  37. 13.5
  38. store charge briefly
  39. 1840
  40. 2.5

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