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Electronics Worksheet: Ohm’s Law – Current and Resistance

Electronics lesson 13: Ohm’s law: find current and resistance · Set 827 · 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 V? (a) V = I ÷ R (b) V = R ÷ I (c) V = I × R (d) V = I + R
  2. 2.🔺 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
  3. 3.🔺 A 5 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  4. 4.🔺 A current of 25 mA flows when 3.75 V is joined across a resistor. What is its resistance (in ohms)?
  5. 5.🔺 A current of 0.2 A flows when 1.6 V is joined across a resistor. What is its resistance (in ohms)?
  6. 6.🔺 A current of 50 mA flows when 16.5 V is joined across a resistor. What is its resistance (in ohms)?
  7. 7.🔺 A 4 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  8. 8.🔺 A 30 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  9. 9.🔺 A 30 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  10. 10.🔺 A 16 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  11. 11.🔺 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
  12. 12.🔺 A 2.5 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  13. 13.🔺 A 4 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  14. 14.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) gets bigger (c) stays the same (d) gets smaller
  15. 15.🔺 A current of 10 mA flows when 2.2 V is joined across a resistor. What is its resistance (in ohms)?
  16. 16.🔺 A current of 2 A flows when 30 V is joined across a resistor. What is its resistance (in ohms)?
  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 2.5 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  19. 19.🔺 A 15 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  20. 20.🔺 A 1.2 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  21. 21.🔺 A current of 25 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  22. 22.🔺 A current of 40 mA flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
  23. 23.🔺 A current of 25 mA flows when 2.5 V is joined across a resistor. What is its resistance (in ohms)?
  24. 24.🔺 A 5 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  25. 25.🔺 A 3 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  26. 26.🔺 A 12 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  27. 27.🔺 A current of 0.2 A flows when 2.4 V is joined across a resistor. What is its resistance (in ohms)?
  28. 28.🔺 A 5.5 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  29. 29.🔺 A current of 1.5 A flows when 22.5 V is joined across a resistor. What is its resistance (in ohms)?
  30. 30.🔺 A 1 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  31. 31.🔺 A 2.4 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  32. 32.🔺 A 5 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  33. 33.🔺 An 8 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  34. 34.🔺 A current of 0.5 A flows when 2.5 V is joined across a resistor. What is its resistance (in ohms)?
  35. 35.🔺 An 18 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  36. 36.🔺 A 5 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
  37. 37.🔺 A 1.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  38. 38.🔺 A current of 2.5 A flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
  39. 39.🔺 A current of 2.5 A flows when 50 V is joined across a resistor. What is its resistance (in ohms)?
  40. 40.🔺 A current of 50 mA flows when 7.5 V is joined across a resistor. What is its resistance (in ohms)?

Answer key

  1. V = I × R
  2. I = V ÷ R
  3. 50
  4. 150
  5. 8
  6. 330
  7. 2
  8. 1.5
  9. 2.5
  10. 40
  11. R = V ÷ I
  12. 0.25
  13. 40
  14. gets smaller
  15. 220
  16. 15
  17. 100
  18. 10
  19. 1.5
  20. 0.2
  21. 120
  22. 150
  23. 100
  24. 25
  25. 20
  26. 1.5
  27. 12
  28. 25
  29. 15
  30. 10
  31. 20
  32. 2.5
  33. 40
  34. 5
  35. 3
  36. 10
  37. 10
  38. 8
  39. 20
  40. 150

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