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Electronics Worksheet: Ohm’s Law – Current and Resistance

Electronics lesson 13: Ohm’s law: find current and resistance · Set 466 · 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 36 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  2. 2.🔺 A 6 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  3. 3.🔺 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
  4. 4.🔺 A 1.5 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  5. 5.🔺 A current of 1 A flows when 15 V is joined across a resistor. What is its resistance (in ohms)?
  6. 6.🔺 A 5 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  7. 7.🔺 A current of 10 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  8. 8.🔺 A current of 3 A flows when 45 V is joined across a resistor. What is its resistance (in ohms)?
  9. 9.🔺 An 18.8 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
  10. 10.🔺 A current of 25 mA flows when 12.5 V is joined across a resistor. What is its resistance (in ohms)?
  11. 11.🔺 A 12 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  12. 12.🔺 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
  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 current of 2 A flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  15. 15.🔺 A current of 20 mA flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  16. 16.🔺 A 1.2 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  17. 17.🔺 A current of 20 mA flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
  18. 18.🔺 A 2.5 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  19. 19.🔺 A current of 2.5 A flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  20. 20.🔺 A current of 3 A flows when 36 V is joined across a resistor. What is its resistance (in ohms)?
  21. 21.🔺 A current of 40 mA flows when 16 V is joined across a resistor. What is its resistance (in ohms)?
  22. 22.🔺 A 4 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  23. 23.🔺 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
  24. 24.🔺 A 7.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  25. 25.🔺 A current of 25 mA flows when 3.75 V is joined across a resistor. What is its resistance (in ohms)?
  26. 26.🔺 A current of 1 A flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  27. 27.🔺 A 2 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  28. 28.🔺 A 2.2 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  29. 29.🔺 A current of 25 mA flows when 11.75 V is joined across a resistor. What is its resistance (in ohms)?
  30. 30.🔺 A 6.25 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  31. 31.🔺 A 7.5 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
  32. 32.🔺 A 3 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
  33. 33.🔺 A current of 20 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  34. 34.🔺 A 0.6 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  35. 35.🔺 A 1.2 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  36. 36.🔺 A 1.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  37. 37.🔺 A 6 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  38. 38.🔺 A 6 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  39. 39.🔺 A 9.4 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
  40. 40.🔺 A current of 2 A flows when 24 V is joined across a resistor. What is its resistance (in ohms)?

Answer key

  1. 3
  2. 40
  3. R = V ÷ I
  4. 0.5
  5. 15
  6. 0.25
  7. 400
  8. 15
  9. 40
  10. 500
  11. 3
  12. V = I × R
  13. I = V ÷ R
  14. 5
  15. 100
  16. 10
  17. 300
  18. 25
  19. 4
  20. 12
  21. 400
  22. 0.5
  23. gets smaller
  24. 50
  25. 150
  26. 10
  27. 0.2
  28. 10
  29. 470
  30. 25
  31. 25
  32. 10
  33. 150
  34. 0.1
  35. 0.1
  36. 0.1
  37. 1.5
  38. 3
  39. 20
  40. 12

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