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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 985 · 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.

NameDateTime takenScore ___ / 40
  1. 1.📏 How many watts (W) is 3.7 kW?
  2. 2.🔺 A 2.4 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  3. 3.True or false: the ammeter measures current. (a) False (b) True
  4. 4.📏 How many watts (W) is 0.4 kW?
  5. 5.🔺 A 12 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  6. 6.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V + I (c) R = V × I (d) R = V ÷ I
  7. 7.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 720 Ω resistor? (a) violet-red-brown (b) violet-red-black (c) red-violet-brown (d) violet-red-red
  8. 8.🧮 Five equal 250 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  9. 9.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  10. 10.🔺 A current of 10 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
  11. 11.True or false: to use old filament bulbs wastes electricity. (a) True (b) False
  12. 12.🔺 A current of 20 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
  13. 13.🧮 A 20 Ω resistor is joined in series with two equal 40 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  14. 14.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 volt (c) 1 watt (d) 1 kilowatt-hour (kWh)
  15. 15.Which of these saves electricity? (a) run fans in empty rooms (b) leave the TV on standby (c) switch off empty rooms (d) iron one shirt at a time
  16. 16.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 50 % (c) 5 % (d) 0 %
  17. 17.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 45 Ω resistor? (a) green-yellow-black (b) yellow-green-black (c) yellow-green-brown (d) green-green-black
  18. 18.🧩 Which part changes electrical energy into movement? (a) a motor (b) a fuse (c) an LED (d) a resistor
  19. 19.Which of these is measured in volts (V)? (a) the push of a cell (b) power (c) resistance (d) how much a part resists
  20. 20.🔺 A current of 2 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  21. 21.🔺 A current of 20 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
  22. 22.True or false: on an LED, the longer leg is the anode (+). (a) True (b) False
  23. 23.🔺 A current of 0.2 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  24. 24.Which of these is measured in amperes (A)? (a) energy used each second (b) the push of a cell (c) current (d) power
  25. 25.🧮 Five equal 500 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  26. 26.True or false: the voltmeter measures current. (a) True (b) False
  27. 27.⚡ A 0.75 W device works on 1.5 V. What current does it take (in amperes)? =
  28. 28.True or false: on an LED, the longer leg is the cathode (−). (a) False (b) True
  29. 29.🔺 A current of 1 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  30. 30.Which of these is measured in watts (W)? (a) how much a part resists (b) the push of a cell (c) voltage (d) power
  31. 31.🌈 Which band is read first on a resistor? (a) the one nearest an end (b) the widest gap (c) any band (d) the gold band
  32. 32.📏 How many amperes (A) is 730 mA? =
  33. 33.⚡ A device works on 5 V and takes 1 A. What is its power (in watts)? =
  34. 34.🌈 A resistor has the colour bands orange, red, brown. What is its value (in ohms)?
  35. 35.🔺 A current of 25 mA flows when 6.25 V is joined across a resistor. What is its resistance (in ohms)?
  36. 36.🧩 Which component glows using little power? (a) diode (b) potentiometer (c) LED (d) capacitor
  37. 37.🧮 Two equal 330 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  38. 38.🔺 An 8.8 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  39. 39.⚡ A device works on 9 V and takes 1.5 A. What is its power (in watts)? =
  40. 40.True or false: on an LED, the round-side leg is the cathode (−). (a) True (b) False

Answer key

  1. 3700
  2. 20
  3. True
  4. 400
  5. 1.5
  6. R = V ÷ I
  7. violet-red-brown
  8. 50
  9. anode (+)
  10. 1.2
  11. True
  12. 9.4
  13. 40
  14. 1 kilowatt-hour (kWh)
  15. switch off empty rooms
  16. 5 %
  17. yellow-green-black
  18. a motor
  19. the push of a cell
  20. 8
  21. 5
  22. True
  23. 1.2
  24. current
  25. 100
  26. False
  27. 0.5
  28. False
  29. 6
  30. power
  31. the one nearest an end
  32. 0.73
  33. 5
  34. 320
  35. 250
  36. LED
  37. 165
  38. 40
  39. 13.5
  40. False

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