# What is the voltage at the ends of a 12 cm long iron wire with a cross-sectional

July 25, 2021 | education

| **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.

One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.