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Electronics Worksheet: Ohm’s Law – Current and Resistance

Electronics lesson 13: Ohm’s law: find current and resistance · Set 720 · 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 40 mA flows when 18.8 V is joined across a resistor. What is its resistance (in ohms)?
  2. 2.🔺 A 5.5 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  3. 3.🔺 A 10 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  4. 4.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets smaller (b) becomes zero (c) stays the same (d) gets bigger
  5. 5.🔺 A current of 40 mA flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
  6. 6.🔺 A 0.8 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  7. 7.🔺 A current of 0.5 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  8. 8.🔺 A current of 2 A flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
  9. 9.🔺 A current of 1.5 A flows when 22.5 V is joined across a resistor. What is its resistance (in ohms)?
  10. 10.🔺 A current of 50 mA flows when 16.5 V is joined across a resistor. What is its resistance (in ohms)?
  11. 11.🔺 A current of 0.25 A flows when 0.5 V is joined across a resistor. What is its resistance (in ohms)?
  12. 12.🔺 A 10 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  13. 13.🔺 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
  14. 14.🔺 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
  15. 15.🔺 A current of 1 A flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
  16. 16.🔺 A current of 20 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  17. 17.🔺 A current of 25 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  18. 18.🔺 A current of 1.5 A flows when 30 V is joined across a resistor. What is its resistance (in ohms)?
  19. 19.🔺 A 30 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  20. 20.🔺 A 3 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  21. 21.🔺 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
  22. 22.🔺 A current of 1.5 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  23. 23.🔺 A current of 3 A flows when 60 V is joined across a resistor. What is its resistance (in ohms)?
  24. 24.🔺 A current of 40 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  25. 25.🔺 A 15 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  26. 26.🔺 A 15 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  27. 27.🔺 A 25 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
  28. 28.🔺 A current of 10 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  29. 29.🔺 A current of 0.2 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  30. 30.🔺 A current of 20 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  31. 31.🔺 A current of 40 mA flows when 8.8 V is joined across a resistor. What is its resistance (in ohms)?
  32. 32.🔺 A 2.5 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  33. 33.🔺 A 3 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  34. 34.🔺 A 3 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  35. 35.🔺 A 2 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  36. 36.🔺 A 30 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  37. 37.🔺 A 5 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  38. 38.🔺 A 25 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  39. 39.🔺 A current of 40 mA flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
  40. 40.🔺 A current of 0.5 A flows when 6 V is joined across a resistor. What is its resistance (in ohms)?

Answer key

  1. 470
  2. 25
  3. 25
  4. gets smaller
  5. 200
  6. 0.2
  7. 6
  8. 6
  9. 15
  10. 330
  11. 2
  12. 40
  13. I = V ÷ R
  14. R = V ÷ I
  15. 8
  16. 150
  17. 200
  18. 20
  19. 2
  20. 25
  21. V = I × R
  22. 2
  23. 20
  24. 100
  25. 2.5
  26. 1.5
  27. 50
  28. 400
  29. 10
  30. 250
  31. 220
  32. 0.25
  33. 1.5
  34. 0.2
  35. 0.1
  36. 1.5
  37. 20
  38. 2.5
  39. 150
  40. 12

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