Determine the length of a nichrome wire with a cross-sectional area of 0.55 mm2, if, with a voltage at its ends of 120 V

Determine the length of a nichrome wire with a cross-sectional area of 0.55 mm2, if, with a voltage at its ends of 120 V, the current passing through the wire is 1.2 A.

Initial data: S (cross-sectional area of nichrome wire) = 0.55 mm2; U (voltage at the ends of the nichrome wire) = 120 V; I (current flowing through the wire) = 1.2 A.

Constants: ρ (resistivity of nichrome, n.o.) = 1.1 Ohm * mm2 / m.

The length of the nichrome wire can be determined from the equality: U / I = R = ρ * l / S, whence l = U * S / (I * ρ).

Let’s calculate: l = 120 * 0.55 / (1.2 * 1.1) = 50 m.

Answer: The length of the nichrome wire is 50 meters.