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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 602 · 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.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 0 % (c) 50 % (d) 5 %
  2. 2.🔺 A current of 10 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  3. 3.🧮 Two resistors in parallel give a total that is … (a) their sum (b) less than either one (c) more than either one (d) always zero
  4. 4.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
  5. 5.⚡ A device works on 3 V and takes 0.2 A. What is its power (in watts)? =
  6. 6.🔺 A current of 10 mA flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
  7. 7.🔺 A current of 0.1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  8. 8.📏 How many ohms (Ω) is 4.9 kΩ?
  9. 9.🌈 A resistor has the colour bands green, black, orange. What is its value in kilo-ohms (kΩ)? =
  10. 10.⚡ Which formula gives electric power? (a) P = V + I (b) P = V × I (c) P = V ÷ I (d) P = I ÷ V
  11. 11.🧮 Two equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  12. 12.⚡ A device works on 9 V and takes 1 A. What is its power (in watts)? =
  13. 13.True or false: the ammeter measures current. (a) False (b) True
  14. 14.⚡ Power tells us … (a) the colour of light (b) the size of a cell (c) the length of a wire (d) energy used each second
  15. 15.🧩 Which part changes electrical energy into movement? (a) a motor (b) a resistor (c) an LED (d) a fuse
  16. 16.True or false: on an LED, the shorter leg is the cathode (−). (a) False (b) True
  17. 17.⚡ A 1.5 W device works on 3 V. What current does it take (in amperes)? =
  18. 18.🧾 Which lamp gives the same light for the least power? (a) a candle (b) a filament bulb (c) an oil lamp (d) an LED lamp
  19. 19.True or false: on an LED, the leg by the flat edge is the anode (+). (a) False (b) True
  20. 20.True or false: an LED glows using little power. (a) False (b) True
  21. 21.💡 An LED is joined to a 6 V battery with no resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) lights up (b) may burn out (c) does not light
  22. 22.🔺 A 12 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  23. 23.💡 What happens if an LED is put in backwards? (a) it lights brighter (b) it makes a sound (c) it does not light (d) it changes colour
  24. 24.💡 Does it save or waste electricity to iron one shirt at a time? (a) saves electricity (b) wastes electricity
  25. 25.🔺 A 3 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  26. 26.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
  27. 27.📏 How many amperes (A) is 1900 mA? =
  28. 28.📏 How many ohms (Ω) is 8.4 kΩ?
  29. 29.Which of these is measured in ohms (Ω)? (a) current (b) voltage (c) the flow of charge (d) resistance
  30. 30.⚡ A 2.4 W device works on 12 V. What current does it take (in amperes)? =
  31. 31.🌈 A resistor has the colour bands red, orange, orange. What is its value in kilo-ohms (kΩ)? =
  32. 32.🔺 A current of 25 mA flows when 8.25 V is joined across a resistor. What is its resistance (in ohms)?
  33. 33.🧮 Two equal 220 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  34. 34.🌈 A resistor has the colour bands brown, black, brown. What is its value (in ohms)?
  35. 35.🧩 A capacitor in a circuit can … (a) spin a wheel (b) make light (c) measure heat (d) store charge briefly
  36. 36.🔺 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
  37. 37.🔺 A current of 2.5 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  38. 38.True or false: the voltmeter measures voltage. (a) False (b) True
  39. 39.Which of these is measured in volts (V)? (a) power (b) energy used each second (c) the flow of charge (d) voltage
  40. 40.🔺 A current of 3 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =

Answer key

  1. 5 %
  2. 1.5
  3. less than either one
  4. 136
  5. 0.6
  6. 100
  7. 1
  8. 4900
  9. 50
  10. P = V × I
  11. 100
  12. 9
  13. True
  14. energy used each second
  15. a motor
  16. True
  17. 0.5
  18. an LED lamp
  19. False
  20. True
  21. may burn out
  22. 2
  23. it does not light
  24. wastes electricity
  25. 1.5
  26. voltmeter
  27. 1.9
  28. 8400
  29. resistance
  30. 0.2
  31. 23
  32. 330
  33. 110
  34. 100
  35. store charge briefly
  36. V = I × R
  37. 50
  38. True
  39. voltage
  40. 9

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