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Electronics Worksheet: Ohm’s Law – Current and Resistance

Electronics lesson 13: Ohm’s law: find current and resistance · Set 131 · 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 0.75 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  2. 2.🔺 A 12 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  3. 3.🔺 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
  4. 4.🔺 A 2.5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  5. 5.🔺 A 23.5 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
  6. 6.🔺 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
  7. 7.🔺 A 15 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  8. 8.🔺 A 10 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  9. 9.🔺 A 5 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  10. 10.🔺 A current of 1 A flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  11. 11.🔺 A current of 40 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  12. 12.🔺 A current of 20 mA flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
  13. 13.🔺 A 2.2 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  14. 14.🔺 A 25 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  15. 15.🔺 A current of 0.1 A flows when 0.5 V is joined across a resistor. What is its resistance (in ohms)?
  16. 16.🔺 A 1 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  17. 17.🔺 A 1.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  18. 18.🔺 A 0.3 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  19. 19.🔺 A 0.2 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  20. 20.🔺 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
  21. 21.🔺 A 6 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
  22. 22.🔺 A current of 20 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  23. 23.🔺 A current of 20 mA flows when 4.4 V is joined across a resistor. What is its resistance (in ohms)?
  24. 24.🔺 A current of 25 mA flows when 2.5 V is joined across a resistor. What is its resistance (in ohms)?
  25. 25.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) becomes zero (c) gets smaller (d) stays the same
  26. 26.🔺 A current of 10 mA flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
  27. 27.🔺 A 13.2 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  28. 28.🔺 A 10 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
  29. 29.🔺 A 6 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  30. 30.🔺 A 4 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  31. 31.🔺 An 8 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  32. 32.🔺 A 1.2 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  33. 33.🔺 A 4.7 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
  34. 34.🔺 A 16.5 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  35. 35.🔺 A current of 10 mA flows when 4.7 V is joined across a resistor. What is its resistance (in ohms)?
  36. 36.🔺 A current of 0.25 A flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  37. 37.🔺 A 3.3 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  38. 38.🔺 A current of 50 mA flows when 7.5 V is joined across a resistor. What is its resistance (in ohms)?
  39. 39.🔺 A current of 1.5 A flows when 30 V is joined across a resistor. What is its resistance (in ohms)?
  40. 40.🔺 A current of 10 mA flows when 2.5 V is joined across a resistor. What is its resistance (in ohms)?

Answer key

  1. 0.25
  2. 3
  3. I = V ÷ R
  4. 0.5
  5. 50
  6. V = I × R
  7. 3
  8. 40
  9. 50
  10. 5
  11. 250
  12. 400
  13. 10
  14. 2.5
  15. 5
  16. 0.25
  17. 10
  18. 0.1
  19. 0.1
  20. R = V ÷ I
  21. 20
  22. 150
  23. 220
  24. 100
  25. gets smaller
  26. 150
  27. 40
  28. 20
  29. 40
  30. 10
  31. 20
  32. 0.1
  33. 10
  34. 50
  35. 470
  36. 20
  37. 10
  38. 150
  39. 20
  40. 250

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