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Electronics Worksheet: Ohm’s Law – Current and Resistance

Electronics lesson 13: Ohm’s law: find current and resistance · Set 458 · 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 1.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  2. 2.🔺 A current of 3 A flows when 36 V is joined across a resistor. What is its resistance (in ohms)?
  3. 3.🔺 A current of 10 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  4. 4.🔺 A 5.5 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  5. 5.🔺 A 2.4 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  6. 6.🔺 A 1 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  7. 7.🔺 A current of 40 mA flows when 4.8 V is joined across a resistor. What is its resistance (in ohms)?
  8. 8.🔺 A current of 25 mA flows when 8.25 V is joined across a resistor. What is its resistance (in ohms)?
  9. 9.🔺 A current of 10 mA flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  10. 10.🔺 A 2.5 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  11. 11.🔺 A 10 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
  12. 12.🔺 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
  13. 13.🔺 A 12 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
  14. 14.🔺 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
  15. 15.🔺 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
  16. 16.🔺 A 0.75 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  17. 17.🔺 A current of 10 mA flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
  18. 18.🔺 A 1.6 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  19. 19.🔺 A current of 20 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  20. 20.🔺 A 2 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  21. 21.🔺 A 15 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  22. 22.🔺 A 0.8 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  23. 23.🔺 A 6.6 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  24. 24.🔺 A current of 25 mA flows when 12.5 V is joined across a resistor. What is its resistance (in ohms)?
  25. 25.🔺 A current of 25 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  26. 26.🔺 A 3 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  27. 27.🔺 An 18.8 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
  28. 28.🔺 A current of 3 A flows when 60 V is joined across a resistor. What is its resistance (in ohms)?
  29. 29.🔺 A 2.5 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  30. 30.🔺 A current of 20 mA flows when 6.6 V is joined across a resistor. What is its resistance (in ohms)?
  31. 31.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) becomes zero (c) gets bigger (d) gets smaller
  32. 32.🔺 A current of 0.5 A flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
  33. 33.🔺 A current of 40 mA flows when 13.2 V is joined across a resistor. What is its resistance (in ohms)?
  34. 34.🔺 A 0.5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  35. 35.🔺 A current of 0.2 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  36. 36.🔺 A 3.75 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  37. 37.🔺 A 16 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  38. 38.🔺 A 2.5 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  39. 39.🔺 A 0.4 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  40. 40.🔺 A current of 25 mA flows when 2.5 V is joined across a resistor. What is its resistance (in ohms)?

Answer key

  1. 10
  2. 12
  3. 300
  4. 25
  5. 0.2
  6. 0.1
  7. 120
  8. 330
  9. 200
  10. 25
  11. 20
  12. R = V ÷ I
  13. 40
  14. I = V ÷ R
  15. V = I × R
  16. 0.25
  17. 100
  18. 0.2
  19. 150
  20. 0.25
  21. 3
  22. 0.2
  23. 20
  24. 500
  25. 400
  26. 0.2
  27. 40
  28. 20
  29. 10
  30. 330
  31. gets smaller
  32. 2
  33. 330
  34. 0.1
  35. 15
  36. 0.25
  37. 40
  38. 0.25
  39. 0.2
  40. 100

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