Labo Élec
electrical lab simulator
Exercise from the chapter "Ohm's law & resistance"
Level 2 of 5 · Skills: Calculate
Compute the resistance of a iron wire 500 m long, 2.5 mm in diameter, with resistivity 0.1 Ω·mm²/m.
ρ = 0.1 Ω·mm²/m · l = 500 m · D = 2.5 mm
Parametric exercise: the values change with every draw; these are one example.
Guided problem in 4 steps: unknown, formula, units, data, result.
S = π·D²/4 = 4.91 mm²; R = ρ·l/S = 0.1 × 500 / 4.91 = 10.2 Ω.