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Electronics Worksheet: Ohm’s Law – Current and Resistance

Electronics lesson 13: Ohm’s law: find current and resistance · Set 29 · 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.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = V ÷ I (c) R = V + I (d) R = I ÷ V
  2. 2.🔺 A current of 0.5 A flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  3. 3.🔺 A 10 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  4. 4.🔺 A 1.2 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  5. 5.🔺 A current of 1.5 A flows when 9 V is joined across a resistor. What is its resistance (in ohms)?
  6. 6.🔺 A 6 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  7. 7.🔺 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
  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 3.75 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  10. 10.🔺 A 3 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  11. 11.🔺 A 1.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  12. 12.🔺 A 2 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  13. 13.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) stays the same (c) gets bigger (d) gets smaller
  14. 14.🔺 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
  15. 15.🔺 A current of 50 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  16. 16.🔺 A current of 0.25 A flows when 3.75 V is joined across a resistor. What is its resistance (in ohms)?
  17. 17.🔺 A current of 0.25 A flows when 1.25 V is joined across a resistor. What is its resistance (in ohms)?
  18. 18.🔺 A current of 0.25 A flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
  19. 19.🔺 A 4.8 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  20. 20.🔺 A current of 0.1 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  21. 21.🔺 An 18.8 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
  22. 22.🔺 A current of 0.5 A flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  23. 23.🔺 A current of 0.1 A flows when 0.8 V is joined across a resistor. What is its resistance (in ohms)?
  24. 24.🔺 An 8 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  25. 25.🔺 A current of 1.5 A flows when 22.5 V is joined across a resistor. What is its resistance (in ohms)?
  26. 26.🔺 A current of 10 mA flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
  27. 27.🔺 A 3 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
  28. 28.🔺 An 11.75 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
  29. 29.🔺 A current of 10 mA flows when 4.7 V is joined across a resistor. What is its resistance (in ohms)?
  30. 30.🔺 A current of 50 mA flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
  31. 31.🔺 A 4 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  32. 32.🔺 A current of 50 mA flows when 12.5 V is joined across a resistor. What is its resistance (in ohms)?
  33. 33.🔺 A current of 1 A flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  34. 34.🔺 A current of 0.2 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  35. 35.🔺 A 4.4 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  36. 36.🔺 A current of 2.5 A flows when 7.5 V is joined across a resistor. What is its resistance (in ohms)?
  37. 37.🔺 A 5 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  38. 38.🔺 A current of 50 mA flows when 16.5 V is joined across a resistor. What is its resistance (in ohms)?
  39. 39.🔺 A 10 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  40. 40.🔺 A 30 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =

Answer key

  1. R = V ÷ I
  2. 8
  3. 40
  4. 0.2
  5. 6
  6. 0.5
  7. V = I × R
  8. 330
  9. 25
  10. 0.2
  11. 10
  12. 10
  13. gets smaller
  14. I = V ÷ R
  15. 200
  16. 15
  17. 5
  18. 6
  19. 40
  20. 20
  21. 40
  22. 10
  23. 8
  24. 1
  25. 15
  26. 100
  27. 10
  28. 25
  29. 470
  30. 120
  31. 20
  32. 250
  33. 5
  34. 10
  35. 20
  36. 3
  37. 50
  38. 330
  39. 2
  40. 2.5

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