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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 998 · 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.🔺 A current of 0.1 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  2. 2.True or false: a thermistor beeps for an alarm. (a) False (b) True
  3. 3.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  4. 4.🧩 A capacitor in a circuit can … (a) measure heat (b) spin a wheel (c) make light (d) store charge briefly
  5. 5.True or false: on an LED, the round-side leg is the anode (+). (a) True (b) False
  6. 6.🔺 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
  7. 7.🔺 A 45 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  8. 8.What does a resistor do? (a) stores a little charge (b) limits the current (c) blows if current is high (d) makes a beeping sound
  9. 9.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = V + R (c) I = V ÷ R (d) I = R ÷ V
  10. 10.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) smaller (c) stay the same (d) bigger
  11. 11.True or false: the voltmeter is joined in series. (a) False (b) True
  12. 12.🌈 Which band is read first on a resistor? (a) the one nearest an end (b) any band (c) the widest gap (d) the gold band
  13. 13.🧾 A 1500 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
  14. 14.🧩 Which part changes electrical energy into movement? (a) a motor (b) a resistor (c) an LED (d) a fuse
  15. 15.📏 How many kilowatts (kW) is 5000 W? =
  16. 16.Which of these is measured in volts (V)? (a) the flow of charge (b) power (c) how much a part resists (d) voltage
  17. 17.⚡ Which formula gives electric power? (a) P = V + I (b) P = V ÷ I (c) P = V × I (d) P = I ÷ V
  18. 18.True or false: on an LED, the shorter leg is the anode (+). (a) True (b) False
  19. 19.⚡ A 12 W device works on 12 V. What current does it take (in amperes)? =
  20. 20.🔺 A 10 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  21. 21.⚡ A device works on 24 V and takes 2 A. What is its power (in watts)? =
  22. 22.🔺 A current of 25 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
  23. 23.🔺 A current of 1.5 A flows when 22.5 V is joined across a resistor. What is its resistance (in ohms)?
  24. 24.🧮 Resistors of 68 Ω, 10 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
  25. 25.True or false: on an LED, the round-side leg is the cathode (−). (a) True (b) False
  26. 26.True or false: on an LED, the leg by the flat edge is the anode (+). (a) False (b) True
  27. 27.Which of these is measured in amperes (A)? (a) the flow of charge (b) the push of a cell (c) voltage (d) power
  28. 28.⚡ A 1.5 W device works on 3 V. What current does it take (in amperes)? =
  29. 29.True or false: a potentiometer is a resistance knob. (a) False (b) True
  30. 30.🌈 A resistor has the colour bands brown, white, orange. What is its value in kilo-ohms (kΩ)? =
  31. 31.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
  32. 32.💡 An LED is joined to a 3 V battery through a 1000 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) may burn out (b) lights up (c) does not light
  33. 33.⚡ A device works on 24 V and takes 1 A. What is its power (in watts)? =
  34. 34.🔺 An 8 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  35. 35.🔺 A current of 20 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  36. 36.🧮 Three equal 150 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  37. 37.What does a capacitor do? (a) blows if current is high (b) stores a little charge (c) beeps for an alarm (d) has coloured bands
  38. 38.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
  39. 39.⚡ A 6 W device works on 3 V. What current does it take (in amperes)? =
  40. 40.🔺 A 4.7 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?

Answer key

  1. 0.5
  2. False
  3. anode (+)
  4. store charge briefly
  5. True
  6. V = I × R
  7. 3
  8. limits the current
  9. I = V ÷ R
  10. bigger
  11. False
  12. the one nearest an end
  13. 12
  14. a motor
  15. 5
  16. voltage
  17. P = V × I
  18. False
  19. 1
  20. 2.5
  21. 48
  22. 8.25
  23. 15
  24. 88
  25. False
  26. False
  27. the flow of charge
  28. 0.5
  29. True
  30. 19
  31. 2300
  32. does not light
  33. 24
  34. 1
  35. 8
  36. 50
  37. stores a little charge
  38. ammeter
  39. 2
  40. 10

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