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Electronics Worksheet: Ohm’s Law – Current and Resistance

Electronics lesson 13: Ohm’s law: find current and resistance · Set 464 · 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 9.4 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
  2. 2.🔺 A 7.5 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  3. 3.🔺 A 7.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  4. 4.🔺 A current of 50 mA flows when 16.5 V is joined across a resistor. What is its resistance (in ohms)?
  5. 5.🔺 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
  6. 6.🔺 A 10 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  7. 7.🔺 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
  8. 8.🔺 A 12 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  9. 9.🔺 A current of 50 mA flows when 25 V is joined across a resistor. What is its resistance (in ohms)?
  10. 10.🔺 A 12 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  11. 11.🔺 A current of 0.25 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  12. 12.🔺 A current of 1 A flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  13. 13.🔺 A 15 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
  14. 14.🔺 A current of 3 A flows when 36 V is joined across a resistor. What is its resistance (in ohms)?
  15. 15.🔺 A 2 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  16. 16.🔺 A 1.5 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  17. 17.🔺 A current of 20 mA flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  18. 18.🔺 A 3 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  19. 19.🔺 A current of 0.25 A flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  20. 20.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) gets smaller (c) gets bigger (d) stays the same
  21. 21.🔺 A current of 25 mA flows when 5.5 V is joined across a resistor. What is its resistance (in ohms)?
  22. 22.🔺 A 2.5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  23. 23.🔺 A 2.5 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  24. 24.🔺 A 3 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  25. 25.🔺 A 30 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  26. 26.🔺 A 1 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  27. 27.🔺 A 1.6 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  28. 28.🔺 A current of 50 mA flows when 12.5 V is joined across a resistor. What is its resistance (in ohms)?
  29. 29.🔺 A current of 20 mA flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
  30. 30.🔺 A current of 0.1 A flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
  31. 31.🔺 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
  32. 32.🔺 A current of 10 mA flows when 1.2 V is joined across a resistor. What is its resistance (in ohms)?
  33. 33.🔺 A 5 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  34. 34.🔺 A current of 0.2 A flows when 0.6 V is joined across a resistor. What is its resistance (in ohms)?
  35. 35.🔺 A 13.2 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  36. 36.🔺 A 5.5 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  37. 37.🔺 A 10 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  38. 38.🔺 A 2 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  39. 39.🔺 A current of 1 A flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  40. 40.🔺 A current of 0.5 A flows when 2.5 V is joined across a resistor. What is its resistance (in ohms)?

Answer key

  1. 20
  2. 2.5
  3. 50
  4. 330
  5. V = I × R
  6. 50
  7. I = V ÷ R
  8. 2
  9. 500
  10. 1.5
  11. 12
  12. 10
  13. 50
  14. 12
  15. 10
  16. 0.25
  17. 100
  18. 0.2
  19. 20
  20. gets smaller
  21. 220
  22. 0.5
  23. 10
  24. 0.25
  25. 1.5
  26. 10
  27. 0.2
  28. 250
  29. 400
  30. 15
  31. R = V ÷ I
  32. 120
  33. 0.5
  34. 3
  35. 40
  36. 25
  37. 25
  38. 20
  39. 4
  40. 5

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