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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 118 · 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 band is read first on a resistor? (a) any band (b) the widest gap (c) the one nearest an end (d) the gold band
  2. 2.🔺 A current of 10 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
  3. 3.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V × I (d) P = V + I
  4. 4.True or false: the ammeter measures voltage. (a) True (b) False
  5. 5.🔺 A current of 0.5 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  6. 6.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) gets bigger (c) gets smaller (d) stays the same
  7. 7.🔺 A 15 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  8. 8.📏 Which unit measures how much a part resists? (a) ampere (A) (b) volt (V) (c) ohm (Ω) (d) watt (W)
  9. 9.🔺 A current of 0.1 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  10. 10.🔺 A current of 1 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  11. 11.💡 Does it save or waste electricity to run fans in empty rooms? (a) wastes electricity (b) saves electricity
  12. 12.⚡ A 9 W device works on 3 V. What current does it take (in amperes)? =
  13. 13.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
  14. 14.🔺 A current of 1 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  15. 15.🔺 A current of 0.5 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  16. 16.Which of these is measured in amperes (A)? (a) the push of a cell (b) current (c) voltage (d) how much a part resists
  17. 17.🧮 Two equal 1000 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  18. 18.⚡ A device works on 9 V and takes 1.5 A. What is its power (in watts)? =
  19. 19.🔺 A current of 0.1 A flows when 0.4 V is joined across a resistor. What is its resistance (in ohms)?
  20. 20.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 7700 Ω resistor? (a) violet-violet-brown (b) violet-violet-orange (c) violet-violet-red (d) violet-grey-red
  21. 21.📏 Which unit measures current? (a) volt (V) (b) ohm (Ω) (c) ampere (A) (d) watt (W)
  22. 22.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) smaller (c) zero (d) bigger
  23. 23.⚡ A device works on 1.5 V and takes 0.1 A. What is its power (in watts)? =
  24. 24.🔺 A current of 2.5 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  25. 25.🔺 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
  26. 26.True or false: on an LED, the shorter leg is the anode (+). (a) True (b) False
  27. 27.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 watt (c) 1 ampere (d) 1 kilowatt-hour (kWh)
  28. 28.🌈 A resistor has the colour bands brown, red, red. What is its value in kilo-ohms (kΩ)? =
  29. 29.🔺 A current of 1.5 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  30. 30.🌈 A resistor has the colour bands white, grey, yellow. What is its value in kilo-ohms (kΩ)? =
  31. 31.💡 A red LED uses 2 V and should get 25 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
  32. 32.🔺 A current of 0.2 A flows when 0.4 V is joined across a resistor. What is its resistance (in ohms)?
  33. 33.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 59 Ω resistor? (a) green-white-black (b) white-green-black (c) blue-white-black (d) green-white-brown
  34. 34.🔺 A current of 10 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
  35. 35.🧮 Two equal 330 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  36. 36.💡 Does it save or waste electricity to unplug idle chargers? (a) saves electricity (b) wastes electricity
  37. 37.🔺 A current of 3 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  38. 38.⚡ A device works on 3 V and takes 0.5 A. What is its power (in watts)? =
  39. 39.🔍 Which is the odd one out? (a) switch off empty rooms (b) leave the TV on standby (c) use LED lamps (d) close the fridge quickly
  40. 40.True or false: on an LED, the round-side leg is the cathode (−). (a) True (b) False

Answer key

  1. the one nearest an end
  2. 1.2
  3. P = V × I
  4. False
  5. 4
  6. gets smaller
  7. 1
  8. ohm (Ω)
  9. 1.2
  10. 4
  11. wastes electricity
  12. 3
  13. 600
  14. 2
  15. 7.5
  16. current
  17. 500
  18. 13.5
  19. 4
  20. violet-violet-red
  21. ampere (A)
  22. bigger
  23. 0.15
  24. 20
  25. R = V ÷ I
  26. False
  27. 1 kilowatt-hour (kWh)
  28. 1.2
  29. 15
  30. 980
  31. 120
  32. 2
  33. green-white-black
  34. 4.7
  35. 165
  36. saves electricity
  37. 60
  38. 1.5
  39. leave the TV on standby
  40. False

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