The resistivity of gold is 244 X 108 ohmsm at room temperatu

The resistivity of gold is 2.44 X 10^-8 ohms(m) at room temperature. A gold wire that is 0.9 mm in diameter and 14 cm long carries a current of 940 mA. What is the resistance of the wire?

Solution

Area of Gold wire

A=pi*D²/4 =pi*(0.9*10^-3)²/4

A=6.36*10^-7 m²

Resistance of the gold wire is

R=pL/A =(2.44*10^-8)*0.14/(6.36*10^-7)

R=5.37*10^-3 ohms