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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 594 · 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 device works on 6 V and takes 0.5 A. What is its power (in watts)? =
  2. 2.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 71000 Ω resistor? (a) brown-violet-orange (b) violet-brown-yellow (c) violet-brown-red (d) violet-brown-orange
  3. 3.🔍 Which is the odd one out? (a) unplug idle chargers (b) leave fridge door open (c) leave the TV on standby (d) use old filament bulbs
  4. 4.🌈 A resistor has the colour bands red, black, orange. What is its value (in ohms)?
  5. 5.🧮 Two equal 220 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  6. 6.🔺 A 1 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  7. 7.🔺 A current of 0.25 A flows when 0.5 V is joined across a resistor. What is its resistance (in ohms)?
  8. 8.What does a motor do? (a) makes things spin (b) is a resistance knob (c) senses how hot it is (d) boosts a small signal
  9. 9.⚡ A device works on 24 V and takes 2 A. What is its power (in watts)? =
  10. 10.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) becomes zero (c) gets bigger (d) gets smaller
  11. 11.True or false: the voltmeter measures voltage. (a) True (b) False
  12. 12.🔺 A current of 3 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  13. 13.🔺 A current of 0.1 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  14. 14.🔺 A current of 40 mA flows when 8.8 V is joined across a resistor. What is its resistance (in ohms)?
  15. 15.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 19000 Ω resistor? (a) brown-white-red (b) brown-white-orange (c) brown-white-yellow (d) white-brown-orange
  16. 16.🧾 A 100 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
  17. 17.🧮 Resistors of 150 Ω, 10 Ω, 50 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
  18. 18.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  19. 19.🔺 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
  20. 20.🧩 A capacitor in a circuit can … (a) spin a wheel (b) measure heat (c) make light (d) store charge briefly
  21. 21.📏 How many kilowatts (kW) is 4200 W? =
  22. 22.📏 How many amperes (A) is 250 mA? =
  23. 23.🔺 A current of 1 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  24. 24.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 320 Ω resistor? (a) orange-red-red (b) red-orange-brown (c) orange-red-brown (d) orange-red-black
  25. 25.What does a potentiometer do? (a) is a resistance knob (b) beeps for an alarm (c) glows using little power (d) makes a beeping sound
  26. 26.🔺 A current of 40 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  27. 27.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  28. 28.🔺 A current of 2.5 A flows when 25 V is joined across a resistor. What is its resistance (in ohms)?
  29. 29.True or false: the flow of charge is measured in watts (W). (a) False (b) True
  30. 30.🧮 Resistors of 330 Ω and 330 Ω are joined in series. What is the total resistance (in ohms)?
  31. 31.⚡ Which formula gives electric power? (a) P = V × I (b) P = V ÷ I (c) P = I ÷ V (d) P = V + I
  32. 32.🔺 A current of 25 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  33. 33.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
  34. 34.True or false: how much a part resists is measured in volts (V). (a) True (b) False
  35. 35.💡 An LED is joined to a 9 V battery with no resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) lights up (b) may burn out (c) does not light
  36. 36.🌈 A resistor has the colour bands green, black, red. What is its value in kilo-ohms (kΩ)? =
  37. 37.🧾 Which lamp gives the same light for the least power? (a) an LED lamp (b) a filament bulb (c) an oil lamp (d) a candle
  38. 38.🌈 A resistor has the colour bands blue, red, red. What is its value (in ohms)?
  39. 39.🔺 A current of 3 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  40. 40.⚡ Power tells us … (a) the length of a wire (b) the size of a cell (c) energy used each second (d) the colour of light

Answer key

  1. 3
  2. violet-brown-orange
  3. unplug idle chargers
  4. 20000
  5. 110
  6. 0.1
  7. 2
  8. makes things spin
  9. 48
  10. gets smaller
  11. True
  12. 36
  13. 0.2
  14. 220
  15. brown-white-orange
  16. 0.4
  17. 220
  18. 10
  19. I = V ÷ R
  20. store charge briefly
  21. 4.2
  22. 0.25
  23. 12
  24. orange-red-brown
  25. is a resistance knob
  26. 6
  27. anode (+)
  28. 10
  29. False
  30. 660
  31. P = V × I
  32. 10
  33. ammeter
  34. False
  35. may burn out
  36. 5
  37. an LED lamp
  38. 6200
  39. 45
  40. energy used each second

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