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Electronics Worksheet: Ohm’s Law – Current and Resistance

Electronics lesson 13: Ohm’s law: find current and resistance · Set 590 · 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.🔺 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
  2. 2.🔺 A current of 2 A flows when 24 V is joined across a resistor. What is its resistance (in ohms)?
  3. 3.🔺 A 2 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  4. 4.🔺 A 25 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  5. 5.🔺 A current of 50 mA flows when 15 V is joined across a resistor. What is its resistance (in ohms)?
  6. 6.🔺 A current of 2 A flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
  7. 7.🔺 A current of 2.5 A flows when 7.5 V is joined across a resistor. What is its resistance (in ohms)?
  8. 8.🔺 A 12 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  9. 9.🔺 A 0.4 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  10. 10.🔺 A current of 2.5 A flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  11. 11.🔺 A current of 25 mA flows when 2.5 V is joined across a resistor. What is its resistance (in ohms)?
  12. 12.🔺 A 30 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  13. 13.🔺 A 16 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  14. 14.🔺 A current of 20 mA flows when 6.6 V is joined across a resistor. What is its resistance (in ohms)?
  15. 15.🔺 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
  16. 16.🔺 A 45 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  17. 17.🔺 A 16.5 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  18. 18.🔺 A current of 0.5 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  19. 19.🔺 A 4.4 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 V is joined across a resistor. What is its resistance (in ohms)?
  21. 21.🔺 A 3 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  22. 22.🔺 A 10 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  23. 23.🔺 An 8 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  24. 24.🔺 A 4 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  25. 25.🔺 A 10 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  26. 26.🔺 A current of 0.2 A flows when 0.4 V is joined across a resistor. What is its resistance (in ohms)?
  27. 27.🔺 A 15 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  28. 28.🔺 A current of 25 mA flows when 5.5 V is joined across a resistor. What is its resistance (in ohms)?
  29. 29.🔺 A 1.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  30. 30.🔺 A current of 0.1 A flows when 0.8 V is joined across a resistor. What is its resistance (in ohms)?
  31. 31.🔺 A 0.8 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  32. 32.🔺 A current of 2.5 A flows when 37.5 V is joined across a resistor. What is its resistance (in ohms)?
  33. 33.🔺 A 2 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  34. 34.🔺 A current of 10 mA flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  35. 35.🔺 A 2 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  36. 36.🔺 A current of 3 A flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
  37. 37.🔺 An 18 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  38. 38.🔺 A current of 50 mA flows when 12.5 V is joined across a resistor. What is its resistance (in ohms)?
  39. 39.🔺 A current of 10 mA flows when 4.7 V is joined across a resistor. What is its resistance (in ohms)?
  40. 40.🔺 A current of 0.1 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?

Answer key

  1. I = V ÷ R
  2. 12
  3. 0.5
  4. 2.5
  5. 300
  6. 6
  7. 3
  8. 1.5
  9. 0.2
  10. 2
  11. 100
  12. 2
  13. 2
  14. 330
  15. gets smaller
  16. 3
  17. 50
  18. 4
  19. 20
  20. 100
  21. 25
  22. 2.5
  23. 40
  24. 0.2
  25. 40
  26. 2
  27. 3
  28. 220
  29. 0.1
  30. 8
  31. 0.2
  32. 15
  33. 0.2
  34. 200
  35. 0.25
  36. 2
  37. 3
  38. 250
  39. 470
  40. 20

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