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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 794 · 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.💡 An LED is joined to a 5 V battery through a 220 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) does not light (b) lights up (c) may burn out
  2. 2.🔺 A current of 3 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  3. 3.⚡ Power tells us … (a) energy used each second (b) the size of a cell (c) the colour of light (d) the length of a wire
  4. 4.💡 An LED is joined to a 9 V battery through a 1000 Ω 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
  5. 5.💡 What does LED stand for? (a) light energy dial (b) large electric dial (c) low energy device (d) light-emitting diode
  6. 6.💡 A red LED uses 2 V and should get 10 mA. It runs from a 6 V supply. What resistor (in ohms) is needed in series?
  7. 7.True or false: the voltmeter is joined across a part. (a) True (b) False
  8. 8.⚡ A 10 W device works on 5 V. What current does it take (in amperes)? =
  9. 9.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 59000 Ω resistor? (a) green-white-yellow (b) green-white-orange (c) white-green-orange (d) green-white-red
  10. 10.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = V + I (c) R = I ÷ V (d) R = V ÷ I
  11. 11.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 6 V supply. What current flows (in mA)?
  12. 12.🔺 A 1.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  13. 13.Which of these is measured in amperes (A)? (a) voltage (b) the push of a cell (c) energy used each second (d) the flow of charge
  14. 14.🔺 A current of 40 mA flows when 4.8 V is joined across a resistor. What is its resistance (in ohms)?
  15. 15.🔺 A 10 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  16. 16.🌈 In the resistor colour code, which number does blue stand for?
  17. 17.💡 An LED is joined to a 6 V battery through a 1000 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) does not light (b) lights up (c) may burn out
  18. 18.📏 How many watts (W) is 1.5 kW?
  19. 19.True or false: a diode beeps for an alarm. (a) True (b) False
  20. 20.🧩 A capacitor in a circuit can … (a) spin a wheel (b) make light (c) measure heat (d) store charge briefly
  21. 21.🧩 Which component makes things spin? (a) motor (b) diode (c) transistor (d) fuse
  22. 22.🧮 A 1.3 V battery is joined to 10 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
  23. 23.💡 Why does an LED need a resistor in series? (a) to change its colour (b) to store charge (c) to make it brighter (d) to limit the current
  24. 24.🌈 In the resistor colour code, which number does grey stand for?
  25. 25.True or false: a motor makes things spin. (a) True (b) False
  26. 26.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 ampere (c) 1 volt (d) 1 kilowatt-hour (kWh)
  27. 27.💡 What happens if an LED is put in backwards? (a) it makes a sound (b) it does not light (c) it lights brighter (d) it changes colour
  28. 28.⚡ Which formula gives electric power? (a) P = V × I (b) P = I ÷ V (c) P = V + I (d) P = V ÷ I
  29. 29.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
  30. 30.🔺 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
  31. 31.🔺 A 2 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  32. 32.🔺 A current of 10 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
  33. 33.🔺 A current of 0.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  34. 34.🧮 Resistors of 20 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
  35. 35.💡 An LED is joined to a 9 V battery through a 220 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) lights up (b) may burn out (c) does not light
  36. 36.🔺 A current of 20 mA flows when 4.4 V is joined across a resistor. What is its resistance (in ohms)?
  37. 37.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  38. 38.⚡ A device works on 5 V and takes 1.5 A. What is its power (in watts)? =
  39. 39.🧩 Which component smooths a wobbly supply? (a) diode (b) motor (c) capacitor (d) resistor
  40. 40.🔺 In the V-I-R triangle, how do we find I? (a) I = V + R (b) I = V ÷ R (c) I = R ÷ V (d) I = V × R

Answer key

  1. lights up
  2. 18
  3. energy used each second
  4. lights up
  5. light-emitting diode
  6. 400
  7. True
  8. 2
  9. green-white-orange
  10. R = V ÷ I
  11. 20
  12. 0.1
  13. the flow of charge
  14. 120
  15. 40
  16. 6
  17. lights up
  18. 1500
  19. False
  20. store charge briefly
  21. motor
  22. 0.1
  23. to limit the current
  24. 8
  25. True
  26. 1 kilowatt-hour (kWh)
  27. it does not light
  28. P = V × I
  29. 920
  30. V = I × R
  31. 0.2
  32. 2.2
  33. 2.5
  34. 70
  35. lights up
  36. 220
  37. anode (+)
  38. 7.5
  39. capacitor
  40. I = V ÷ R

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