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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 793 · 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.🧮 Two resistors in parallel give a total that is … (a) their sum (b) more than either one (c) always zero (d) less than either one
  2. 2.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) gets smaller (c) becomes zero (d) gets bigger
  3. 3.📏 Which unit measures current? (a) ampere (A) (b) watt (W) (c) volt (V) (d) ohm (Ω)
  4. 4.🌈 A resistor has the colour bands blue, red, orange. What is its value (in ohms)?
  5. 5.🔺 A 0.2 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  6. 6.⚡ A device works on 24 V and takes 0.5 A. What is its power (in watts)? =
  7. 7.🔺 A 2 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  8. 8.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  9. 9.🔺 A current of 1 A flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
  10. 10.⚡ Power tells us … (a) energy used each second (b) the size of a cell (c) the length of a wire (d) the colour of light
  11. 11.🔺 A current of 1.5 A flows when 22.5 V is joined across a resistor. What is its resistance (in ohms)?
  12. 12.🔺 A current of 10 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
  13. 13.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  14. 14.True or false: current is measured in volts (V). (a) False (b) True
  15. 15.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = R ÷ V (c) I = V ÷ R (d) I = V + R
  16. 16.True or false: resistance is measured in amperes (A). (a) True (b) False
  17. 17.🌈 A resistor has the colour bands green, violet, black. What is its value (in ohms)?
  18. 18.True or false: a thermistor makes a beeping sound. (a) False (b) True
  19. 19.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 4.25 V supply. What current flows (in mA)?
  20. 20.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 50 % (c) 0 % (d) 25 %
  21. 21.True or false: on an LED, the shorter leg is the anode (+). (a) False (b) True
  22. 22.🧩 Which component limits the current? (a) buzzer (b) LDR (c) resistor (d) motor
  23. 23.📏 How many watts (W) is 0.2 kW?
  24. 24.🔺 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
  25. 25.📏 How many ohms (Ω) is 9.9 kΩ?
  26. 26.🌈 A resistor has the colour bands white, white, red. What is its value in kilo-ohms (kΩ)? =
  27. 27.🔺 A current of 0.25 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  28. 28.🧮 Resistors of 22 Ω and 68 Ω are joined in series. What is the total resistance (in ohms)?
  29. 29.🔺 A current of 1.5 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  30. 30.True or false: on an LED, the longer leg is the anode (+). (a) True (b) False
  31. 31.🧩 Which part changes electrical energy into movement? (a) a resistor (b) an LED (c) a motor (d) a fuse
  32. 32.📏 Which unit measures the push of a cell? (a) watt (W) (b) ampere (A) (c) ohm (Ω) (d) volt (V)
  33. 33.🧩 Which component smooths a wobbly supply? (a) transistor (b) capacitor (c) LED (d) diode
  34. 34.📏 How many amperes (A) is 1230 mA? =
  35. 35.🌈 A resistor has the colour bands white, white, brown. What is its value (in ohms)?
  36. 36.🔺 A current of 10 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  37. 37.🔺 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
  38. 38.🧩 Which component makes things spin? (a) thermistor (b) fuse (c) capacitor (d) motor
  39. 39.🔺 A 5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  40. 40.⚡ A 0.75 W device works on 1.5 V. What current does it take (in amperes)? =

Answer key

  1. less than either one
  2. gets smaller
  3. ampere (A)
  4. 62000
  5. 0.1
  6. 12
  7. 10
  8. cathode (−)
  9. 20
  10. energy used each second
  11. 15
  12. 2.2
  13. cathode (−)
  14. False
  15. I = V ÷ R
  16. False
  17. 57
  18. False
  19. 15
  20. 5 %
  21. False
  22. resistor
  23. 200
  24. R = V ÷ I
  25. 9900
  26. 9.9
  27. 3.75
  28. 90
  29. 15
  30. True
  31. a motor
  32. volt (V)
  33. capacitor
  34. 1.23
  35. 990
  36. 2
  37. V = I × R
  38. motor
  39. 1
  40. 0.5

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