What is the voltage at the ends of a 12 cm long iron wire with a cross-sectional area of 0.04 mm2 if the current flowing through this wire is 240 mA?
Initial data: l (length of the iron wire) = 12 cm; S (cross-sectional area of the wire) = 0.04 mm ^ 2, I (current flowing through the wire) = 240 mA = 0.24 A.
Reference data: ρ (resistivity of iron) = 0.1 Ohm * mm ^ 2 / m.
SI system: l = 12 cm = 0.12 m.
The voltage at the ends of the iron wire: U = I * R, where R (wire resistance) = ρ * l / S and U = I * ρ * l / S.
Calculation: U = 0.24 * 0.1 * 0.12 / 0.04 = 0.072 V = 72 mV.
Answer: The voltage at the ends of the wire is 72 mV.
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