What is the current strength in an iron wire 120 cm long with a section of 0.1 mm2, if the voltage at the ends is 36 V.

What is the current strength in an iron wire 120 cm long with a section of 0.1 mm2, if the voltage at the ends is 36 V. The specific electrical resistance of copper is 0.1 Ohm * mm2 / m.

Initial data: l (length of the iron wire) = 120 cm; S (section of iron wire) = 0.1 mm2; U (voltage at the ends of the iron wire) = 36 V.

Reference data: according to the condition of the problem ρ (specific electrical resistance of iron) = 0.1 Ohm * mm2 / m.

SI system: l = 120 cm = 1.2 m.

1) Resistance of this iron wire: R = ρ * l / S = 0.1 * 1.2 / 0.1 = 1.2 Ohm.

2) The strength of the current in the iron wire: I = U / R = 36 / 1.2 = 30 A.

Answer: In an iron wire, the effective current is 30 A.