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Electronics Worksheet: Ohm’s Law – Current and Resistance

Electronics lesson 13: Ohm’s law: find current and resistance · Set 94 · 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 20 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  2. 2.🔺 A current of 0.1 A flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
  3. 3.🔺 A 5 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  4. 4.🔺 A 6 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  5. 5.🔺 A current of 40 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  6. 6.🔺 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
  7. 7.🔺 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
  8. 8.🔺 A current of 0.2 A flows when 0.8 V is joined across a resistor. What is its resistance (in ohms)?
  9. 9.🔺 A 1 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  10. 10.🔺 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
  11. 11.🔺 A 12.5 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
  12. 12.🔺 A 0.5 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  13. 13.🔺 A 2.5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  14. 14.🔺 An 18.8 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
  15. 15.🔺 A current of 40 mA flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
  16. 16.🔺 A current of 25 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  17. 17.🔺 A current of 0.2 A flows when 2.4 V is joined across a resistor. What is its resistance (in ohms)?
  18. 18.🔺 A current of 0.5 A flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  19. 19.🔺 A current of 25 mA flows when 8.25 V is joined across a resistor. What is its resistance (in ohms)?
  20. 20.🔺 A current of 25 mA flows when 5.5 V is joined across a resistor. What is its resistance (in ohms)?
  21. 21.🔺 A current of 10 mA flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  22. 22.🔺 A current of 0.2 A flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  23. 23.🔺 A 12.5 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  24. 24.🔺 A current of 20 mA flows when 9.4 V is joined across a resistor. What is its resistance (in ohms)?
  25. 25.🔺 A 2 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  26. 26.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) stays the same (c) gets smaller (d) becomes zero
  27. 27.🔺 A 7.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  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 10 mA flows when 1.2 V is joined across a resistor. What is its resistance (in ohms)?
  30. 30.🔺 A current of 25 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  31. 31.🔺 A current of 2 A flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  32. 32.🔺 An 8.25 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  33. 33.🔺 A 6 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  34. 34.🔺 A current of 10 mA flows when 4.7 V is joined across a resistor. What is its resistance (in ohms)?
  35. 35.🔺 A 4 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  36. 36.🔺 A 30 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  37. 37.🔺 A 25 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  38. 38.🔺 A 2 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  39. 39.🔺 A 6 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  40. 40.🔺 An 8 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?

Answer key

  1. 1
  2. 10
  3. 2.5
  4. 50
  5. 250
  6. I = V ÷ R
  7. V = I × R
  8. 4
  9. 0.5
  10. R = V ÷ I
  11. 25
  12. 0.25
  13. 0.5
  14. 40
  15. 500
  16. 120
  17. 12
  18. 20
  19. 330
  20. 220
  21. 200
  22. 20
  23. 50
  24. 470
  25. 10
  26. gets smaller
  27. 50
  28. 25
  29. 120
  30. 200
  31. 2
  32. 25
  33. 40
  34. 470
  35. 10
  36. 1.5
  37. 2.5
  38. 20
  39. 2
  40. 40

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