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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 515 · 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 ohms (Ω) is 2.5 kΩ?
  2. 2.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
  3. 3.⚡ A 9 W device works on 3 V. What current does it take (in amperes)? =
  4. 4.🧮 A 7.5 V battery is joined to 3 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
  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.🧮 Five equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  7. 7.💡 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
  8. 8.🔺 A current of 40 mA flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
  9. 9.True or false: to leave fridge door open saves electricity. (a) True (b) False
  10. 10.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
  11. 11.⚡ A 9 W device works on 6 V. What current does it take (in amperes)? =
  12. 12.🔺 A current of 50 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
  13. 13.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets smaller (b) stays the same (c) becomes zero (d) gets bigger
  14. 14.🌈 In the resistor colour code, which number does violet stand for?
  15. 15.True or false: power is measured in ohms (Ω). (a) True (b) False
  16. 16.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 kilowatt-hour (kWh) (c) 1 volt (d) 1 watt
  17. 17.🔺 A 0.5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  18. 18.⚡ Power tells us … (a) the size of a cell (b) the length of a wire (c) the colour of light (d) energy used each second
  19. 19.📏 How many amperes (A) is 1980 mA? =
  20. 20.🔺 A 36 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  21. 21.True or false: on an LED, the round-side leg is the anode (+). (a) True (b) False
  22. 22.🧮 Five equal 125 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  23. 23.True or false: a resistor is a resistance knob. (a) False (b) True
  24. 24.🧮 A 4 V battery is joined to 4 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
  25. 25.🔺 A 3.3 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  26. 26.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) zero (c) stay the same (d) smaller
  27. 27.🔺 An 18 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  28. 28.🔺 A 1 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  29. 29.Which of these is measured in amperes (A)? (a) energy used each second (b) how much a part resists (c) resistance (d) current
  30. 30.🔺 A current of 0.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  31. 31.🔺 A current of 10 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  32. 32.True or false: power is measured in volts (V). (a) False (b) True
  33. 33.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 39 Ω resistor? (a) yellow-white-black (b) orange-white-brown (c) orange-white-black (d) white-orange-black
  34. 34.🔺 A current of 0.2 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  35. 35.True or false: power is measured in amperes (A). (a) False (b) True
  36. 36.🔺 A current of 0.25 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  37. 37.🧮 A 1.1 V battery is joined to 3 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
  38. 38.🧮 A 470 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)?
  39. 39.🔺 A current of 0.25 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  40. 40.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?

Answer key

  1. 2500
  2. 230
  3. 3
  4. 0.5
  5. P = V × I
  6. 20
  7. lights up
  8. 200
  9. False
  10. saves electricity
  11. 1.5
  12. 6
  13. gets smaller
  14. 7
  15. False
  16. 1 kilowatt-hour (kWh)
  17. 0.1
  18. energy used each second
  19. 1.98
  20. 3
  21. True
  22. 25
  23. False
  24. 0.25
  25. 10
  26. bigger
  27. 1.5
  28. 10
  29. current
  30. 2.5
  31. 1
  32. False
  33. orange-white-black
  34. 1.6
  35. False
  36. 8
  37. 0.1
  38. 490
  39. 1
  40. 1840

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