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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 492 · 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.What does a fuse do? (a) turns a fan or wheels (b) blows if current is high (c) is a resistance knob (d) lets current go one way
  2. 2.🧩 Which component limits the current? (a) thermistor (b) resistor (c) motor (d) capacitor
  3. 3.Which of these saves electricity? (a) leave fridge door open (b) iron one shirt at a time (c) run fans in empty rooms (d) switch off empty rooms
  4. 4.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 6800 Ω resistor? (a) blue-grey-brown (b) blue-grey-red (c) grey-blue-red (d) blue-grey-orange
  5. 5.🌈 In the resistor colour code, which number does grey stand for?
  6. 6.🔺 A 1 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  7. 7.🔺 A current of 40 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
  8. 8.🧩 Which component lets current go one way? (a) diode (b) fuse (c) LED (d) potentiometer
  9. 9.🔍 Which is the odd one out? (a) switch off empty rooms (b) set the AC to 24 °C (c) use old filament bulbs (d) unplug idle chargers
  10. 10.📏 Which unit measures voltage? (a) watt (W) (b) ohm (Ω) (c) ampere (A) (d) volt (V)
  11. 11.🔺 A 7.5 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  12. 12.True or false: to run fans in empty rooms wastes electricity. (a) False (b) True
  13. 13.🔺 A 7.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  14. 14.🌈 A resistor has the colour bands grey, white, orange. What is its value in kilo-ohms (kΩ)? =
  15. 15.🔍 Which is the odd one out? (a) iron one shirt at a time (b) use LED lamps (c) leave fridge door open (d) run fans in empty rooms
  16. 16.True or false: how much a part resists is measured in volts (V). (a) True (b) False
  17. 17.True or false: on an LED, the longer leg is the cathode (−). (a) True (b) False
  18. 18.🧮 A 5.5 V battery is joined to 5 Ω and 6 Ω resistors in series. What current flows (in amperes)? =
  19. 19.⚡ A device works on 1.5 V and takes 2 A. What is its power (in watts)? =
  20. 20.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  21. 21.💡 A blue LED uses 3 V and should get 20 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
  22. 22.True or false: on an LED, the shorter leg is the anode (+). (a) True (b) False
  23. 23.📏 Which unit measures resistance? (a) ohm (Ω) (b) volt (V) (c) ampere (A) (d) watt (W)
  24. 24.💡 What does LED stand for? (a) light energy dial (b) light-emitting diode (c) large electric dial (d) low energy device
  25. 25.🔺 A current of 2.5 A flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  26. 26.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter
  27. 27.True or false: to close the fridge quickly wastes electricity. (a) True (b) False
  28. 28.⚡ A 3 W device works on 6 V. What current does it take (in amperes)? =
  29. 29.⚡ A device works on 9 V and takes 0.5 A. What is its power (in watts)? =
  30. 30.🔺 A current of 3 A flows when 9 V is joined across a resistor. What is its resistance (in ohms)?
  31. 31.True or false: the push of a cell is measured in volts (V). (a) False (b) True
  32. 32.🔺 A current of 1 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  33. 33.🧾 A 50 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
  34. 34.🧩 Which component beeps for an alarm? (a) thermistor (b) LED (c) buzzer (d) motor
  35. 35.🔺 A 6 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  36. 36.🧮 A 1.6 V battery is joined to 2 Ω and 6 Ω resistors in series. What current flows (in amperes)? =
  37. 37.📏 In the water-pipe picture of a circuit, voltage is like … (a) the tap handle (b) the water pressure (c) the pipe colour (d) the water tank lid
  38. 38.🔺 A 4.4 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  39. 39.True or false: a potentiometer stores a little charge. (a) False (b) True
  40. 40.🔺 A current of 50 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =

Answer key

  1. blows if current is high
  2. resistor
  3. switch off empty rooms
  4. blue-grey-red
  5. 8
  6. 0.1
  7. 20
  8. diode
  9. use old filament bulbs
  10. volt (V)
  11. 2.5
  12. True
  13. 50
  14. 89
  15. use LED lamps
  16. False
  17. False
  18. 0.5
  19. 3
  20. anode (+)
  21. 300
  22. False
  23. ohm (Ω)
  24. light-emitting diode
  25. 2
  26. ammeter
  27. False
  28. 0.5
  29. 4.5
  30. 3
  31. True
  32. 12
  33. 0.4
  34. buzzer
  35. 2
  36. 0.2
  37. the water pressure
  38. 20
  39. False
  40. 5

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