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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 647 · 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 of these is measured in volts (V)? (a) the flow of charge (b) how much a part resists (c) energy used each second (d) voltage
  2. 2.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 65 Ω resistor? (a) blue-green-brown (b) green-blue-black (c) violet-green-black (d) blue-green-black
  3. 3.True or false: a potentiometer smooths a wobbly supply. (a) False (b) True
  4. 4.🔺 A 5 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  5. 5.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V × I (c) P = V + I (d) P = V ÷ I
  6. 6.🔺 A current of 25 mA flows when 11.75 V is joined across a resistor. What is its resistance (in ohms)?
  7. 7.🔺 In the V-I-R triangle, how do we find R? (a) R = V ÷ I (b) R = V + I (c) R = V × I (d) R = I ÷ V
  8. 8.📏 Which unit measures how much a part resists? (a) volt (V) (b) ampere (A) (c) ohm (Ω) (d) watt (W)
  9. 9.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I × R (c) V = I ÷ R (d) V = I + R
  10. 10.⚡ A 9 W device works on 3 V. What current does it take (in amperes)? =
  11. 11.🔺 A current of 20 mA flows when 6.6 V is joined across a resistor. What is its resistance (in ohms)?
  12. 12.🧾 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
  13. 13.🔺 A 60 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  14. 14.🔺 A current of 20 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
  15. 15.True or false: resistance is measured in ohms (Ω). (a) True (b) False
  16. 16.🧮 Two resistors in parallel give a total that is … (a) their sum (b) less than either one (c) always zero (d) more than either one
  17. 17.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  18. 18.🌈 A resistor has the colour bands green, white, red. What is its value (in ohms)?
  19. 19.🔺 A 2 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  20. 20.🔺 A 2 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  21. 21.📏 How many milliamperes (mA) is 2.41 A?
  22. 22.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  23. 23.⚡ A 0.9 W device works on 9 V. What current does it take (in amperes)? =
  24. 24.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
  25. 25.🌈 Which band is read first on a resistor? (a) the one nearest an end (b) the gold band (c) the widest gap (d) any band
  26. 26.🧮 Two equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  27. 27.🌈 In the resistor colour code, which number does brown stand for?
  28. 28.🌈 A resistor has the colour bands green, grey, red. What is its value in kilo-ohms (kΩ)? =
  29. 29.⚡ A 1.8 W device works on 9 V. What current does it take (in amperes)? =
  30. 30.⚡ A device works on 6 V and takes 3 A. What is its power (in watts)? =
  31. 31.🔺 A 15 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  32. 32.True or false: power is measured in watts (W). (a) True (b) False
  33. 33.📏 How many milliamperes (mA) is 2.95 A?
  34. 34.🌈 A resistor has the colour bands green, blue, black. What is its value (in ohms)?
  35. 35.🧩 Which part changes electrical energy into movement? (a) a motor (b) a resistor (c) an LED (d) a fuse
  36. 36.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 kilowatt-hour (kWh) (c) 1 ampere (d) 1 volt
  37. 37.💡 Does it save or waste electricity to run fans in empty rooms? (a) saves electricity (b) wastes electricity
  38. 38.🧮 A 47 Ω resistor is joined in series with two equal 1000 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  39. 39.🔺 A current of 1 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  40. 40.🔺 A 4.5 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =

Answer key

  1. voltage
  2. blue-green-black
  3. False
  4. 50
  5. P = V × I
  6. 470
  7. R = V ÷ I
  8. ohm (Ω)
  9. V = I × R
  10. 3
  11. 330
  12. an LED lamp
  13. 3
  14. 6.6
  15. True
  16. less than either one
  17. anode (+)
  18. 5900
  19. 1
  20. 20
  21. 2410
  22. cathode (−)
  23. 0.1
  24. 1840
  25. the one nearest an end
  26. 50
  27. 1
  28. 5.8
  29. 0.2
  30. 18
  31. 3
  32. True
  33. 2950
  34. 56
  35. a motor
  36. 1 kilowatt-hour (kWh)
  37. wastes electricity
  38. 547
  39. 6
  40. 1.5

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