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Electronics Worksheet: Ohm’s Law – Current and Resistance

Electronics lesson 13: Ohm’s law: find current and resistance · Set 122 · 40 questions
TalentJR

Remember (Cover what you want): I = V ÷ R (amperes = volts ÷ ohms). R = V ÷ I (ohms = volts ÷ amperes); use amperes, not mA, in the formula. Example: 5 V and 25 mA (0.025 A) → R = 5 ÷ 0.025 = 200 Ω.

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  1. 1.🔺 A current of 25 mA flows when 12.5 V is joined across a resistor. What is its resistance (in ohms)?
  2. 2.🔺 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
  3. 3.🔺 A current of 0.2 A flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
  4. 4.🔺 A 5.5 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  5. 5.🔺 A current of 0.2 A flows when 1.2 V is joined across a resistor. What is its resistance (in ohms)?
  6. 6.🔺 A current of 25 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  7. 7.🔺 In the V-I-R triangle, how do we find V? (a) V = I × R (b) V = R ÷ I (c) V = I ÷ R (d) V = I + R
  8. 8.🔺 A current of 10 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  9. 9.🔺 A current of 40 mA flows when 13.2 V is joined across a resistor. What is its resistance (in ohms)?
  10. 10.🔺 A current of 50 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  11. 11.🔺 A current of 10 mA flows when 2.5 V is joined across a resistor. What is its resistance (in ohms)?
  12. 12.🔺 A 4.8 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  13. 13.🔺 An 8.25 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  14. 14.🔺 A current of 20 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  15. 15.🔺 A current of 50 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  16. 16.🔺 A 4 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  17. 17.🔺 A current of 50 mA flows when 23.5 V is joined across a resistor. What is its resistance (in ohms)?
  18. 18.🔺 A current of 3 A flows when 24 V is joined across a resistor. What is its resistance (in ohms)?
  19. 19.🔺 An 8.8 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  20. 20.🔺 A current of 10 mA flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
  21. 21.🔺 A current of 2 A flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
  22. 22.🔺 A current of 0.2 A flows when 0.6 V is joined across a resistor. What is its resistance (in ohms)?
  23. 23.🔺 A 6 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  24. 24.🔺 A current of 1 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  25. 25.🔺 A current of 50 mA flows when 15 V is joined across a resistor. What is its resistance (in ohms)?
  26. 26.🔺 A 12.5 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  27. 27.🔺 A current of 1 A flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
  28. 28.🔺 A current of 50 mA flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
  29. 29.🔺 A current of 0.1 A flows when 0.8 V is joined across a resistor. What is its resistance (in ohms)?
  30. 30.🔺 A current of 40 mA flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
  31. 31.🔺 A 6 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
  32. 32.🔺 A current of 25 mA flows when 7.5 V is joined across a resistor. What is its resistance (in ohms)?
  33. 33.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) becomes zero (c) stays the same (d) gets smaller
  34. 34.🔺 A current of 40 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  35. 35.🔺 A 30 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  36. 36.🔺 A current of 25 mA flows when 11.75 V is joined across a resistor. What is its resistance (in ohms)?
  37. 37.🔺 A 45 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  38. 38.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V × R (c) I = V ÷ R (d) I = V + R
  39. 39.🔺 A current of 50 mA flows when 16.5 V is joined across a resistor. What is its resistance (in ohms)?
  40. 40.🔺 A 50 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =

Answer key

  1. 500
  2. R = V ÷ I
  3. 5
  4. 25
  5. 6
  6. 400
  7. V = I × R
  8. 500
  9. 330
  10. 200
  11. 250
  12. 40
  13. 25
  14. 250
  15. 100
  16. 40
  17. 470
  18. 8
  19. 40
  20. 150
  21. 3
  22. 3
  23. 50
  24. 2
  25. 300
  26. 50
  27. 8
  28. 400
  29. 8
  30. 200
  31. 20
  32. 300
  33. gets smaller
  34. 100
  35. 2.5
  36. 470
  37. 3
  38. I = V ÷ R
  39. 330
  40. 2.5

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