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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 994 · 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 unit measures how much a part resists? (a) watt (W) (b) volt (V) (c) ohm (Ω) (d) ampere (A)
  2. 2.🔺 A current of 50 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  3. 3.True or false: on an LED, the shorter leg is the cathode (−). (a) True (b) False
  4. 4.💡 Does it save or waste electricity to use LED lamps? (a) saves electricity (b) wastes electricity
  5. 5.⚡ Power tells us … (a) the size of a cell (b) the colour of light (c) the length of a wire (d) energy used each second
  6. 6.🔺 A current of 2.5 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  7. 7.True or false: the ammeter is joined in series. (a) True (b) False
  8. 8.📏 How many amperes (A) is 1700 mA? =
  9. 9.🧮 A 150 Ω resistor is joined in series with two equal 200 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  10. 10.📏 How many milliamperes (mA) is 2.7 A?
  11. 11.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = V + I (c) R = I ÷ V (d) R = V ÷ I
  12. 12.🧮 A 0.8 V battery is joined to 6 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
  13. 13.🧮 Two resistors in parallel give a total that is … (a) always zero (b) less than either one (c) more than either one (d) their sum
  14. 14.🧮 Two equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  15. 15.⚡ A 12 W device works on 6 V. What current does it take (in amperes)? =
  16. 16.💡 What happens if an LED is put in backwards? (a) it does not light (b) it makes a sound (c) it changes colour (d) it lights brighter
  17. 17.🌈 A resistor has the colour bands yellow, violet, yellow. What is its value in kilo-ohms (kΩ)? =
  18. 18.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  19. 19.True or false: a buzzer stores a little charge. (a) True (b) False
  20. 20.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) an LED lamp (c) a candle (d) a filament bulb
  21. 21.🔺 A current of 50 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  22. 22.🔺 A current of 25 mA flows when 8.25 V is joined across a resistor. What is its resistance (in ohms)?
  23. 23.🔺 A current of 1.5 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  24. 24.🧮 Two equal 1000 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  25. 25.🧾 A 100 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
  26. 26.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  27. 27.🧮 A 3.5 V battery is joined to 8 Ω and 6 Ω resistors in series. What current flows (in amperes)? =
  28. 28.🌈 A resistor has the colour bands white, grey, brown. What is its value (in ohms)?
  29. 29.🔺 A current of 0.25 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  30. 30.🔺 A 24 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  31. 31.📏 Which unit measures the flow of charge? (a) volt (V) (b) watt (W) (c) ohm (Ω) (d) ampere (A)
  32. 32.🔺 A current of 0.25 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  33. 33.💡 Does it save or waste electricity to iron one shirt at a time? (a) saves electricity (b) wastes electricity
  34. 34.📏 How many watts (W) is 4.9 kW?
  35. 35.⚡ A 0.6 W device works on 6 V. What current does it take (in amperes)? =
  36. 36.Which of these is measured in ohms (Ω)? (a) how much a part resists (b) energy used each second (c) voltage (d) the flow of charge
  37. 37.🔺 A current of 3 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  38. 38.⚡ A device works on 1.5 V and takes 1.5 A. What is its power (in watts)? =
  39. 39.🧮 A 470 Ω resistor is joined in series with two equal 10 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  40. 40.True or false: the flow of charge is measured in amperes (A). (a) False (b) True

Answer key

  1. ohm (Ω)
  2. 5
  3. True
  4. saves electricity
  5. energy used each second
  6. 10
  7. True
  8. 1.7
  9. 250
  10. 2700
  11. R = V ÷ I
  12. 0.1
  13. less than either one
  14. 100
  15. 2
  16. it does not light
  17. 470
  18. cathode (−)
  19. False
  20. an LED lamp
  21. 7.5
  22. 330
  23. 12
  24. 500
  25. 0.8
  26. cathode (−)
  27. 0.25
  28. 980
  29. 3
  30. 3
  31. ampere (A)
  32. 0.5
  33. wastes electricity
  34. 4900
  35. 0.1
  36. how much a part resists
  37. 9
  38. 2.25
  39. 475
  40. True

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