Calculate the current flowing through a copper wire 200m long and 0.25mm ^ at a voltage of 12V.

Wire resistance R, Ohm, can be found by the formula

R = ρ * L / S,

where ρ is the specific resistance of the wire material, Ohm * mm² / m;

L and S – length, m, and cross-sectional area, mm², wires.

The current strength I, A, is determined by Ohm’s law for a section of the circuit:

I = U / R,

where U is the potential difference (voltage) at the ends of the section, V.


I = U / (ρ * L / S) = U * S / (ρ * L);

I = 12 * 0.25 / (0.017 * 200) ≈ 0.88 A.

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