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Electronics Worksheet: Ohm’s Law – Current and Resistance

Electronics lesson 13: Ohm’s law: find current and resistance · Set 98 · 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 50 mA flows when 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 I? (a) I = V ÷ R (b) I = V × R (c) I = R ÷ V (d) I = V + R
  3. 3.🔺 A current of 3 A flows when 60 V is joined across a resistor. What is its resistance (in ohms)?
  4. 4.🔺 A 20 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
  5. 5.🔺 A current of 40 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  6. 6.🔺 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
  7. 7.🔺 A current of 20 mA flows when 9.4 V is joined across a resistor. What is its resistance (in ohms)?
  8. 8.🔺 A 15 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  9. 9.🔺 A 1.5 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  10. 10.🔺 A 30 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  11. 11.🔺 A 16.5 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  12. 12.🔺 A 12 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  13. 13.🔺 A current of 1.5 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  14. 14.🔺 A current of 10 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  15. 15.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I ÷ R (c) V = I + R (d) V = I × R
  16. 16.🔺 A 6 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  17. 17.🔺 A current of 40 mA flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
  18. 18.🔺 A 2 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  19. 19.🔺 A 2.2 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  20. 20.🔺 A 1.2 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  21. 21.🔺 A 5 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  22. 22.🔺 A 2 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  23. 23.🔺 A current of 1.5 A flows when 22.5 V is joined across a resistor. What is its resistance (in ohms)?
  24. 24.🔺 A 7.5 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  25. 25.🔺 A 4.8 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  26. 26.🔺 A current of 3 A flows when 45 V is joined across a resistor. What is its resistance (in ohms)?
  27. 27.🔺 A 0.5 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  28. 28.🔺 A 0.4 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  29. 29.🔺 A current of 20 mA flows when 6.6 V is joined across a resistor. What is its resistance (in ohms)?
  30. 30.🔺 A current of 25 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  31. 31.🔺 A 4 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  32. 32.🔺 A 15 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  33. 33.🔺 A 5 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  34. 34.🔺 A current of 1.5 A flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
  35. 35.🔺 A current of 0.1 A flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
  36. 36.🔺 A current of 0.1 A flows when 0.6 V is joined across a resistor. What is its resistance (in ohms)?
  37. 37.🔺 A 20 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  38. 38.🔺 A 10 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
  39. 39.🔺 A current of 0.25 A flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
  40. 40.🔺 A 3.75 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =

Answer key

  1. 100
  2. I = V ÷ R
  3. 20
  4. 40
  5. 100
  6. R = V ÷ I
  7. 470
  8. 1
  9. 0.25
  10. 2.5
  11. 50
  12. 2
  13. 2
  14. 500
  15. V = I × R
  16. 2
  17. 200
  18. 0.1
  19. 10
  20. 0.1
  21. 20
  22. 0.25
  23. 15
  24. 2.5
  25. 40
  26. 15
  27. 0.25
  28. 0.1
  29. 330
  30. 200
  31. 0.2
  32. 1.5
  33. 25
  34. 8
  35. 15
  36. 6
  37. 2
  38. 20
  39. 4
  40. 0.25

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