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Electronics Worksheet: Ohm’s Law – Current and Resistance

Electronics lesson 13: Ohm’s law: find current and resistance · Set 407 · 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 25 mA flows when 11.75 V is joined across a resistor. What is its resistance (in ohms)?
  2. 2.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) becomes zero (c) gets smaller (d) stays the same
  3. 3.🔺 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
  4. 4.🔺 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
  5. 5.🔺 A current of 1 A flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
  6. 6.🔺 A 3 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  7. 7.🔺 A current of 3 A flows when 36 V is joined across a resistor. What is its resistance (in ohms)?
  8. 8.🔺 A 30 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  9. 9.🔺 A current of 0.5 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  10. 10.🔺 A current of 25 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  11. 11.🔺 A current of 10 mA flows when 4.7 V is joined across a resistor. What is its resistance (in ohms)?
  12. 12.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = I + R (c) V = I × R (d) V = R ÷ I
  13. 13.🔺 A current of 0.25 A flows when 0.75 V is joined across a resistor. What is its resistance (in ohms)?
  14. 14.🔺 A current of 25 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  15. 15.🔺 A 7.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  16. 16.🔺 A 0.8 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  17. 17.🔺 A 20 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  18. 18.🔺 A 4 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  19. 19.🔺 A 1.2 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  20. 20.🔺 A 6 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  21. 21.🔺 A 2 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  22. 22.🔺 A current of 3 A flows when 45 V is joined across a resistor. What is its resistance (in ohms)?
  23. 23.🔺 A 2 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  24. 24.🔺 A 12 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  25. 25.🔺 A 7.5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  26. 26.🔺 A current of 20 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  27. 27.🔺 A current of 20 mA flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
  28. 28.🔺 A current of 40 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  29. 29.🔺 A current of 0.25 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  30. 30.🔺 A current of 50 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  31. 31.🔺 A current of 20 mA flows when 4.4 V is joined across a resistor. What is its resistance (in ohms)?
  32. 32.🔺 A current of 1.5 A flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
  33. 33.🔺 A 10 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
  34. 34.🔺 A current of 50 mA flows when 23.5 V is joined across a resistor. What is its resistance (in ohms)?
  35. 35.🔺 An 18.8 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
  36. 36.🔺 A 4 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  37. 37.🔺 A 10 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  38. 38.🔺 A current of 2 A flows when 24 V is joined across a resistor. What is its resistance (in ohms)?
  39. 39.🔺 A 6.6 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  40. 40.🔺 A current of 2.5 A flows when 10 V is joined across a resistor. What is its resistance (in ohms)?

Answer key

  1. 470
  2. gets smaller
  3. I = V ÷ R
  4. R = V ÷ I
  5. 6
  6. 0.5
  7. 12
  8. 3
  9. 4
  10. 120
  11. 470
  12. V = I × R
  13. 3
  14. 200
  15. 50
  16. 0.2
  17. 2.5
  18. 0.2
  19. 0.1
  20. 50
  21. 0.5
  22. 15
  23. 0.2
  24. 1
  25. 1.5
  26. 150
  27. 400
  28. 100
  29. 8
  30. 200
  31. 220
  32. 8
  33. 20
  34. 470
  35. 40
  36. 0.5
  37. 50
  38. 12
  39. 20
  40. 4

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