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Electronics Worksheet: Ohm’s Law – Current and Resistance

Electronics lesson 13: Ohm’s law: find current and resistance · Set 317 · 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.

NameDateTime takenScore ___ / 40
  1. 1.🔺 A current of 3 A flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
  2. 2.🔺 In the V-I-R triangle, how do we find V? (a) V = I × R (b) V = I ÷ R (c) V = R ÷ I (d) V = I + R
  3. 3.🔺 A 0.6 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  4. 4.🔺 A current of 40 mA flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
  5. 5.🔺 A current of 40 mA flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
  6. 6.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets smaller (b) gets bigger (c) becomes zero (d) stays the same
  7. 7.🔺 A 16.5 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  8. 8.🔺 A 2.4 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  9. 9.🔺 A current of 1 A flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  10. 10.🔺 A current of 40 mA flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
  11. 11.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = I ÷ V (c) R = V + I (d) R = V ÷ I
  12. 12.🔺 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
  13. 13.🔺 A current of 20 mA flows when 9.4 V is joined across a resistor. What is its resistance (in ohms)?
  14. 14.🔺 A current of 1 A flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
  15. 15.🔺 A 0.5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  16. 16.🔺 A current of 2.5 A flows when 30 V is joined across a resistor. What is its resistance (in ohms)?
  17. 17.🔺 A 22.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  18. 18.🔺 A current of 10 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  19. 19.🔺 A 20 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  20. 20.🔺 A 6 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  21. 21.🔺 A current of 20 mA flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  22. 22.🔺 A 2 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  23. 23.🔺 A 3 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  24. 24.🔺 An 11.75 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
  25. 25.🔺 A current of 25 mA flows when 5.5 V is joined across a resistor. What is its resistance (in ohms)?
  26. 26.🔺 A 4 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  27. 27.🔺 A current of 50 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  28. 28.🔺 A current of 50 mA flows when 23.5 V is joined across a resistor. What is its resistance (in ohms)?
  29. 29.🔺 A 3 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  30. 30.🔺 A 7.5 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  31. 31.🔺 A 13.2 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  32. 32.🔺 A current of 50 mA flows when 11 V is joined across a resistor. What is its resistance (in ohms)?
  33. 33.🔺 A current of 20 mA flows when 2.4 V is joined across a resistor. What is its resistance (in ohms)?
  34. 34.🔺 A 7.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  35. 35.🔺 A 37.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  36. 36.🔺 A current of 25 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  37. 37.🔺 A current of 0.1 A flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
  38. 38.🔺 A current of 1 A flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  39. 39.🔺 A 5 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
  40. 40.🔺 A current of 1.5 A flows when 9 V is joined across a resistor. What is its resistance (in ohms)?

Answer key

  1. 4
  2. V = I × R
  3. 0.2
  4. 300
  5. 150
  6. gets smaller
  7. 50
  8. 20
  9. 5
  10. 200
  11. R = V ÷ I
  12. I = V ÷ R
  13. 470
  14. 12
  15. 0.1
  16. 12
  17. 1.5
  18. 300
  19. 2
  20. 40
  21. 100
  22. 0.2
  23. 1.5
  24. 25
  25. 220
  26. 10
  27. 100
  28. 470
  29. 25
  30. 2.5
  31. 40
  32. 220
  33. 120
  34. 50
  35. 2.5
  36. 400
  37. 10
  38. 10
  39. 10
  40. 6

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