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Electronics Worksheet: Ohm’s Law – Current and Resistance

Electronics lesson 13: Ohm’s law: find current and resistance · Set 995 · 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 current of 0.1 A flows when 0.5 V is joined across a resistor. What is its resistance (in ohms)?
  2. 2.🔺 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
  3. 3.🔺 A 20 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
  4. 4.🔺 A current of 2.5 A flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
  5. 5.🔺 A 6 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
  6. 6.🔺 A 15 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  7. 7.🔺 A current of 20 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  8. 8.🔺 A 5 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  9. 9.🔺 A 6 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  10. 10.🔺 A 36 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  11. 11.🔺 A current of 10 mA flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
  12. 12.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V × I (c) R = V ÷ I (d) R = V + I
  13. 13.🔺 A 3 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  14. 14.🔺 A 4 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  15. 15.🔺 A current of 20 mA flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
  16. 16.🔺 A current of 20 mA flows when 4.4 V is joined across a resistor. What is its resistance (in ohms)?
  17. 17.🔺 A current of 2.5 A flows when 50 V is joined across a resistor. What is its resistance (in ohms)?
  18. 18.🔺 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
  19. 19.🔺 A current of 0.1 A flows when 0.3 V is joined across a resistor. What is its resistance (in ohms)?
  20. 20.🔺 A current of 25 mA flows when 12.5 V is joined across a resistor. What is its resistance (in ohms)?
  21. 21.🔺 A current of 0.1 A flows when 1.2 V is joined across a resistor. What is its resistance (in ohms)?
  22. 22.🔺 A current of 50 mA flows when 11 V is joined across a resistor. What is its resistance (in ohms)?
  23. 23.🔺 A 12.5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  24. 24.🔺 A 6 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  25. 25.🔺 A current of 2.5 A flows when 12.5 V is joined across a resistor. What is its resistance (in ohms)?
  26. 26.🔺 A 10 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  27. 27.🔺 A current of 20 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  28. 28.🔺 A 0.5 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  29. 29.🔺 A 10 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
  30. 30.🔺 A 7.5 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  31. 31.🔺 A current of 10 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  32. 32.🔺 A current of 25 mA flows when 7.5 V is joined across a resistor. What is its resistance (in ohms)?
  33. 33.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) becomes zero (c) gets bigger (d) gets smaller
  34. 34.🔺 A 2.4 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  35. 35.🔺 A 5 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  36. 36.🔺 A current of 20 mA flows when 2.4 V is joined across a resistor. What is its resistance (in ohms)?
  37. 37.🔺 A 9 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  38. 38.🔺 A current of 20 mA flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  39. 39.🔺 A current of 25 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  40. 40.🔺 A 4.7 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?

Answer key

  1. 5
  2. V = I × R
  3. 2.5
  4. 8
  5. 20
  6. 3
  7. 250
  8. 50
  9. 1
  10. 3
  11. 100
  12. R = V ÷ I
  13. 25
  14. 10
  15. 300
  16. 220
  17. 20
  18. I = V ÷ R
  19. 3
  20. 500
  21. 12
  22. 220
  23. 2.5
  24. 3
  25. 5
  26. 2.5
  27. 500
  28. 0.25
  29. 20
  30. 2.5
  31. 500
  32. 300
  33. gets smaller
  34. 20
  35. 20
  36. 120
  37. 1.5
  38. 100
  39. 200
  40. 10

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