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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 31 · 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.📏 Voltmeter or ammeter: which one measures current? (a) ammeter (b) voltmeter
  2. 2.🔍 Which is the odd one out? (a) iron one shirt at a time (b) unplug idle chargers (c) switch off empty rooms (d) use LED lamps
  3. 3.📏 How many milliamperes (mA) is 0.82 A?
  4. 4.💡 What does LED stand for? (a) low energy device (b) light energy dial (c) large electric dial (d) light-emitting diode
  5. 5.🧮 A 1.6 V battery is joined to 6 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
  6. 6.🌈 A resistor has the colour bands violet, violet, black. What is its value (in ohms)?
  7. 7.🌈 A resistor has the colour bands grey, violet, orange. What is its value (in ohms)?
  8. 8.🔺 A current of 0.5 A flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
  9. 9.🔺 A current of 20 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  10. 10.⚡ A 1.5 W device works on 1.5 V. What current does it take (in amperes)? =
  11. 11.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
  12. 12.🔍 Which is the odd one out? (a) iron one shirt at a time (b) leave the TV on standby (c) close the fridge quickly (d) leave fridge door open
  13. 13.True or false: an LED glows using little power. (a) True (b) False
  14. 14.True or false: an LED limits the current. (a) True (b) False
  15. 15.🔺 A current of 25 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
  16. 16.True or false: a thermistor has coloured bands. (a) True (b) False
  17. 17.⚡ A device works on 12 V and takes 0.2 A. What is its power (in watts)? =
  18. 18.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
  19. 19.🔺 A current of 50 mA flows when 16.5 V is joined across a resistor. What is its resistance (in ohms)?
  20. 20.True or false: a fuse blows if current is high. (a) True (b) False
  21. 21.💡 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
  22. 22.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 kilowatt-hour (kWh) (c) 1 watt (d) 1 ampere
  23. 23.True or false: the push of a cell is measured in volts (V). (a) True (b) False
  24. 24.📏 Which unit measures current? (a) ohm (Ω) (b) watt (W) (c) ampere (A) (d) volt (V)
  25. 25.📏 How many kilo-ohms (kΩ) is 6400 Ω? =
  26. 26.🧮 Two equal 330 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  27. 27.🧮 Resistors of 47 Ω, 470 Ω and 68 Ω are joined in series. What is the total resistance (in ohms)?
  28. 28.What does a transistor do? (a) smooths a wobbly supply (b) glows using little power (c) boosts a small signal (d) is a resistance knob
  29. 29.🔺 A 36 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  30. 30.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) stay the same (c) bigger (d) zero
  31. 31.🔺 A current of 20 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  32. 32.🧮 Two equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  33. 33.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
  34. 34.True or false: to run fans in empty rooms saves electricity. (a) True (b) False
  35. 35.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) becomes zero (c) gets smaller (d) gets bigger
  36. 36.🌈 A resistor has the colour bands white, white, yellow. What is its value in kilo-ohms (kΩ)? =
  37. 37.True or false: the ammeter is joined in series. (a) False (b) True
  38. 38.🧩 Which part changes electrical energy into sound? (a) a resistor (b) a diode (c) a buzzer (d) a capacitor
  39. 39.🔺 A current of 10 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
  40. 40.🌈 A resistor has the colour bands white, red, black. What is its value (in ohms)?

Answer key

  1. ammeter
  2. iron one shirt at a time
  3. 820
  4. light-emitting diode
  5. 0.2
  6. 77
  7. 87000
  8. 2
  9. 2
  10. 1
  11. ammeter
  12. close the fridge quickly
  13. True
  14. False
  15. 6.25
  16. False
  17. 2.4
  18. 2300
  19. 330
  20. True
  21. it does not light
  22. 1 kilowatt-hour (kWh)
  23. True
  24. ampere (A)
  25. 6.4
  26. 165
  27. 585
  28. boosts a small signal
  29. 3
  30. bigger
  31. 500
  32. 100
  33. voltmeter
  34. False
  35. gets smaller
  36. 990
  37. True
  38. a buzzer
  39. 3
  40. 92

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