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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 55 · 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 unit measures voltage? (a) ohm (Ω) (b) volt (V) (c) ampere (A) (d) watt (W)
  2. 2.🧩 Which component has coloured bands? (a) LED (b) LDR (c) motor (d) resistor
  3. 3.🔺 In the V-I-R triangle, how do we find V? (a) V = I × R (b) V = I + R (c) V = I ÷ R (d) V = R ÷ I
  4. 4.💡 A red LED uses 2 V and should get 20 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
  5. 5.🔺 A current of 40 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  6. 6.🧮 Resistors of 150 Ω and 470 Ω are joined in series. What is the total resistance (in ohms)?
  7. 7.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
  8. 8.💡 Does it save or waste electricity to iron one shirt at a time? (a) saves electricity (b) wastes electricity
  9. 9.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
  10. 10.🔺 A current of 3 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  11. 11.🌈 In the resistor colour code, which number does violet stand for?
  12. 12.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
  13. 13.True or false: the voltmeter is joined across a part. (a) False (b) True
  14. 14.🔺 A 10 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  15. 15.📏 How many ohms (Ω) is 4.1 kΩ?
  16. 16.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
  17. 17.🧮 A 50 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)?
  18. 18.🌈 In the resistor colour code, which number does green stand for?
  19. 19.🌈 In the resistor colour code, which number does grey stand for?
  20. 20.💡 An LED is joined to a 6 V battery through a 220 Ω resistor; the leg next to the flat edge of its rim goes to the + side. What happens? (a) does not light (b) lights up (c) may burn out
  21. 21.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V × I (d) P = V ÷ I
  22. 22.🔺 A current of 0.5 A flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  23. 23.🔺 A current of 2.5 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  24. 24.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
  25. 25.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets smaller (b) becomes zero (c) stays the same (d) gets bigger
  26. 26.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter
  27. 27.📏 Which unit measures power? (a) ampere (A) (b) volt (V) (c) ohm (Ω) (d) watt (W)
  28. 28.💡 A red LED uses 2 V and should get 10 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
  29. 29.💡 An LED is joined to a 6 V battery through a 470 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) does not light (b) lights up (c) may burn out
  30. 30.🔺 A 13.2 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  31. 31.🔺 A 2 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  32. 32.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
  33. 33.📏 How many amperes (A) is 2650 mA? =
  34. 34.🌈 Which band is read first on a resistor? (a) the widest gap (b) any band (c) the one nearest an end (d) the gold band
  35. 35.🧩 Which component stores a little charge? (a) buzzer (b) fuse (c) capacitor (d) diode
  36. 36.🧾 A 2000 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
  37. 37.🔺 A current of 1.5 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  38. 38.🔺 In the V-I-R triangle, how do we find R? (a) R = V ÷ I (b) R = I ÷ V (c) R = V × I (d) R = V + I
  39. 39.🧮 A 4.5 V battery is joined to 6 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
  40. 40.💡 A red LED uses 2 V and should get 25 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?

Answer key

  1. volt (V)
  2. resistor
  3. V = I × R
  4. 150
  5. 8
  6. 620
  7. 345
  8. wastes electricity
  9. 1150
  10. 15
  11. 7
  12. ammeter
  13. True
  14. 2
  15. 4100
  16. 230
  17. 60
  18. 5
  19. 8
  20. does not light
  21. P = V × I
  22. 8
  23. 15
  24. voltmeter
  25. gets smaller
  26. ammeter
  27. watt (W)
  28. 300
  29. does not light
  30. 40
  31. 0.2
  32. 2300
  33. 2.65
  34. the one nearest an end
  35. capacitor
  36. 20
  37. 6
  38. R = V ÷ I
  39. 0.25
  40. 400

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