Electronics Worksheet: Ohm’s Law – Current and Resistance
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.
NameDateTime takenScore ___ / 40
- 1.🔺 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
- 2.🔺 A current of 1.5 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
- 3.🔺 A current of 0.2 A flows when 2.4 V is joined across a resistor. What is its resistance (in ohms)?
- 4.🔺 A 1.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
- 5.🔺 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
- 6.🔺 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
- 7.🔺 A 10 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
- 8.🔺 A current of 2 A flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
- 9.🔺 A current of 0.5 A flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
- 10.🔺 A 15 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
- 11.🔺 A current of 20 mA flows when 9.4 V is joined across a resistor. What is its resistance (in ohms)?
- 12.🔺 A current of 2.5 A flows when 30 V is joined across a resistor. What is its resistance (in ohms)?
- 13.🔺 A 0.6 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
- 14.🔺 A 3 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
- 15.🔺 A 4 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
- 16.🔺 A 0.75 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
- 17.🔺 A 3.75 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
- 18.🔺 A 7.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
- 19.🔺 A 10 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
- 20.🔺 A current of 10 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
- 21.🔺 A 4 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
- 22.🔺 An 18 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
- 23.🔺 A 30 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
- 24.🔺 A current of 1 A flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
- 25.🔺 A 37.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
- 26.🔺 A 3 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
- 27.🔺 A 6 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
- 28.🔺 A 15 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
- 29.🔺 A 6 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
- 30.🔺 A 2.5 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
- 31.🔺 A 12 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
- 32.🔺 A 5 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
- 33.🔺 A 60 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
- 34.🔺 A 0.6 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
- 35.🔺 A current of 50 mA flows when 7.5 V is joined across a resistor. What is its resistance (in ohms)?
- 36.🔺 An 8 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
- 37.🔺 A current of 0.2 A flows when 0.6 V is joined across a resistor. What is its resistance (in ohms)?
- 38.🔺 A 10 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
- 39.🔺 A current of 10 mA flows when 2.5 V is joined across a resistor. What is its resistance (in ohms)?
- 40.🔺 A 0.8 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
Answer key
- I = V ÷ R
- 2
- 12
- 0.1
- R = V ÷ I
- V = I × R
- 2
- 2
- 2
- 50
- 470
- 12
- 0.1
- 1.5
- 2
- 0.25
- 0.25
- 0.5
- 2.5
- 400
- 0.5
- 3
- 2.5
- 5
- 2.5
- 1
- 0.5
- 1
- 1.5
- 10
- 1.5
- 0.25
- 3
- 0.2
- 150
- 1
- 3
- 25
- 250
- 0.1
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