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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 153 · 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.⚡ Power tells us … (a) the colour of light (b) the length of a wire (c) energy used each second (d) the size of a cell
  2. 2.True or false: to leave the TV on standby saves electricity. (a) True (b) False
  3. 3.Which of these saves electricity? (a) iron one shirt at a time (b) leave fridge door open (c) run fans in empty rooms (d) switch off empty rooms
  4. 4.🌈 A resistor has the colour bands brown, red, brown. What is its value (in ohms)?
  5. 5.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter
  6. 6.True or false: the voltmeter measures current. (a) False (b) True
  7. 7.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 0 % (c) 50 % (d) 5 %
  8. 8.🔺 A current of 25 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
  9. 9.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  10. 10.🧮 Resistors of 47 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
  11. 11.📏 How many kilowatts (kW) is 2100 W? =
  12. 12.🔍 Which is the odd one out? (a) use LED lamps (b) run fans in empty rooms (c) leave fridge door open (d) use old filament bulbs
  13. 13.⚡ A device works on 3 V and takes 0.1 A. What is its power (in watts)? =
  14. 14.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
  15. 15.🔺 A current of 0.25 A flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
  16. 16.Which of these saves electricity? (a) leave the TV on standby (b) iron one shirt at a time (c) leave fridge door open (d) set the AC to 24 °C
  17. 17.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V × I (d) P = V + I
  18. 18.📏 How many kilo-ohms (kΩ) is 2900 Ω? =
  19. 19.🌈 A resistor has the colour bands yellow, blue, yellow. What is its value in kilo-ohms (kΩ)? =
  20. 20.📏 How many kilowatts (kW) is 4400 W? =
  21. 21.🔺 A 13.2 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  22. 22.🧩 Which component blows if current is high? (a) LDR (b) fuse (c) thermistor (d) potentiometer
  23. 23.🧮 Resistors of 50 Ω, 150 Ω and 100 Ω are joined in series. What is the total resistance (in ohms)?
  24. 24.🔺 A current of 0.1 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  25. 25.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I × R (c) V = I + R (d) V = I ÷ R
  26. 26.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 69000 Ω resistor? (a) white-blue-orange (b) blue-white-yellow (c) blue-white-red (d) blue-white-orange
  27. 27.🌈 A resistor has the colour bands red, blue, red. What is its value (in ohms)?
  28. 28.🧮 Four equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  29. 29.🧩 Which component has coloured bands? (a) transistor (b) resistor (c) capacitor (d) buzzer
  30. 30.🔺 A current of 40 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
  31. 31.📏 How many ohms (Ω) is 2.5 kΩ?
  32. 32.📏 How many milliamperes (mA) is 2.33 A?
  33. 33.🔍 Which is the odd one out? (a) switch off empty rooms (b) use LED lamps (c) leave fridge door open (d) unplug idle chargers
  34. 34.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) smaller (c) bigger (d) stay the same
  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 current of 20 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
  37. 37.Which of these is measured in ohms (Ω)? (a) power (b) the flow of charge (c) voltage (d) resistance
  38. 38.🔺 A current of 10 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  39. 39.⚡ A device works on 5 V and takes 1.5 A. What is its power (in watts)? =
  40. 40.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = V + I (c) R = V ÷ I (d) R = I ÷ V

Answer key

  1. energy used each second
  2. False
  3. switch off empty rooms
  4. 120
  5. ammeter
  6. False
  7. 5 %
  8. 11.75
  9. anode (+)
  10. 97
  11. 2.1
  12. use LED lamps
  13. 0.3
  14. voltmeter
  15. 6
  16. set the AC to 24 °C
  17. P = V × I
  18. 2.9
  19. 460
  20. 4.4
  21. 40
  22. fuse
  23. 300
  24. 0.5
  25. V = I × R
  26. blue-white-orange
  27. 2600
  28. 10
  29. resistor
  30. 20
  31. 2500
  32. 2330
  33. leave fridge door open
  34. bigger
  35. gets smaller
  36. 10
  37. resistance
  38. 4
  39. 7.5
  40. R = V ÷ I

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