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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 679 · 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.True or false: voltage is measured in watts (W). (a) True (b) False
  2. 2.🧮 A 220 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)?
  3. 3.🔺 A 5 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  4. 4.🌈 A resistor has the colour bands green, yellow, red. What is its value in kilo-ohms (kΩ)? =
  5. 5.💡 An LED is joined to a 5 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
  6. 6.💡 Does it save or waste electricity to leave fridge door open? (a) wastes electricity (b) saves electricity
  7. 7.🔍 Which is the odd one out? (a) close the fridge quickly (b) iron one shirt at a time (c) use daylight to read (d) unplug idle chargers
  8. 8.🔺 A 25 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
  9. 9.🧮 A 1.5 V battery is joined to 12 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
  10. 10.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter
  11. 11.🔺 A 7.5 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
  12. 12.🌈 A resistor has the colour bands red, yellow, red. What is its value in kilo-ohms (kΩ)? =
  13. 13.🧾 A 1500 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  14. 14.⚡ A device works on 1.5 V and takes 0.5 A. What is its power (in watts)? =
  15. 15.Which of these is measured in volts (V)? (a) voltage (b) power (c) how much a part resists (d) resistance
  16. 16.🔺 A current of 2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  17. 17.⚡ Power tells us … (a) the colour of light (b) the size of a cell (c) the length of a wire (d) energy used each second
  18. 18.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 volt (c) 1 ampere (d) 1 kilowatt-hour (kWh)
  19. 19.🔺 A current of 25 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
  20. 20.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to a 5 V supply. What current flows (in mA)?
  21. 21.True or false: to use LED lamps saves electricity. (a) False (b) True
  22. 22.True or false: an LED lets current go one way. (a) False (b) True
  23. 23.🌈 A resistor has the colour bands brown, brown, brown. What is its value (in ohms)?
  24. 24.💡 What happens if an LED is put in backwards? (a) it makes a sound (b) it changes colour (c) it does not light (d) it lights brighter
  25. 25.🧮 A 220 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)?
  26. 26.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 1024 (b) 10 (c) 1000 (d) 100
  27. 27.🌈 In the resistor colour code, which number does brown stand for?
  28. 28.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 13 Ω resistor? (a) red-orange-black (b) brown-orange-brown (c) brown-orange-black (d) orange-brown-black
  29. 29.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  30. 30.What does a motor do? (a) stores a little charge (b) limits the current (c) senses how bright it is (d) turns a fan or wheels
  31. 31.True or false: a buzzer beeps for an alarm. (a) False (b) True
  32. 32.🔺 A 0.6 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  33. 33.🔺 A current of 2.5 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  34. 34.🔺 A current of 50 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  35. 35.🔺 A current of 50 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
  36. 36.📏 How many kilo-ohms (kΩ) is 1200 Ω? =
  37. 37.🔺 A 2.2 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  38. 38.🔺 A 1.6 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  39. 39.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  40. 40.💡 Does it save or waste electricity to iron one shirt at a time? (a) saves electricity (b) wastes electricity

Answer key

  1. False
  2. 720
  3. 50
  4. 5.4
  5. lights up
  6. wastes electricity
  7. iron one shirt at a time
  8. 50
  9. 0.1
  10. ammeter
  11. 25
  12. 2.4
  13. 3
  14. 0.75
  15. voltage
  16. 40
  17. energy used each second
  18. 1 kilowatt-hour (kWh)
  19. 3
  20. 10
  21. True
  22. False
  23. 110
  24. it does not light
  25. 320
  26. 1000
  27. 1
  28. brown-orange-black
  29. cathode (−)
  30. turns a fan or wheels
  31. True
  32. 0.2
  33. 7.5
  34. 10
  35. 16.5
  36. 1.2
  37. 10
  38. 0.2
  39. anode (+)
  40. wastes electricity

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