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Electronics Worksheet: Ohm’s Law – Current and Resistance

Electronics lesson 13: Ohm’s law: find current and resistance · Set 120 · 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.🔺 An 18 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  2. 2.🔺 A current of 10 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  3. 3.🔺 A current of 2.5 A flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  4. 4.🔺 A current of 1 A flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  5. 5.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) stays the same (c) gets smaller (d) becomes zero
  6. 6.🔺 A 1 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  7. 7.🔺 A 50 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  8. 8.🔺 A 12 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  9. 9.🔺 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
  10. 10.🔺 A current of 20 mA flows when 9.4 V is joined across a resistor. What is its resistance (in ohms)?
  11. 11.🔺 A current of 25 mA flows when 12.5 V is joined across a resistor. What is its resistance (in ohms)?
  12. 12.🔺 A current of 2 A flows when 30 V is joined across a resistor. What is its resistance (in ohms)?
  13. 13.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = V × R (c) I = V + R (d) I = R ÷ V
  14. 14.🔺 A 2 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  15. 15.🔺 A 5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  16. 16.🔺 A current of 40 mA flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
  17. 17.🔺 A current of 50 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  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 6 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  20. 20.🔺 A current of 2.5 A flows when 37.5 V is joined across a resistor. What is its resistance (in ohms)?
  21. 21.🔺 A current of 25 mA flows when 3.75 V is joined across a resistor. What is its resistance (in ohms)?
  22. 22.🔺 A 5 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  23. 23.🔺 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
  24. 24.🔺 A 2 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  25. 25.🔺 A current of 10 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  26. 26.🔺 A 6 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  27. 27.🔺 A current of 20 mA flows when 2.4 V is joined across a resistor. What is its resistance (in ohms)?
  28. 28.🔺 A current of 25 mA flows when 8.25 V is joined across a resistor. What is its resistance (in ohms)?
  29. 29.🔺 A current of 10 mA flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  30. 30.🔺 A 20 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  31. 31.🔺 A current of 0.2 A flows when 1.2 V is joined across a resistor. What is its resistance (in ohms)?
  32. 32.🔺 A current of 50 mA flows when 16.5 V is joined across a resistor. What is its resistance (in ohms)?
  33. 33.🔺 A 24 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  34. 34.🔺 A current of 50 mA flows when 7.5 V is joined across a resistor. What is its resistance (in ohms)?
  35. 35.🔺 A current of 0.2 A flows when 2.4 V is joined across a resistor. What is its resistance (in ohms)?
  36. 36.🔺 A 2.4 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  37. 37.🔺 A 1 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  38. 38.🔺 A 0.8 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  39. 39.🔺 A current of 0.1 A flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
  40. 40.🔺 A 36 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =

Answer key

  1. 3
  2. 500
  3. 4
  4. 4
  5. gets smaller
  6. 10
  7. 2.5
  8. 1
  9. R = V ÷ I
  10. 470
  11. 500
  12. 15
  13. I = V ÷ R
  14. 20
  15. 1
  16. 200
  17. 100
  18. 300
  19. 50
  20. 15
  21. 150
  22. 20
  23. V = I × R
  24. 0.1
  25. 400
  26. 40
  27. 120
  28. 330
  29. 200
  30. 1
  31. 6
  32. 330
  33. 3
  34. 150
  35. 12
  36. 20
  37. 0.1
  38. 0.1
  39. 10
  40. 3

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