Question

Part A

What diameter must a copper wire have if its resistance is to be the same as that of an equal length of aluminum wire with diameter 1.64 mm ?

Answer 1

Resistivity of copper =1.72 ×10^-8

Resistivity of aluminum=2.65 ×10^-8

length is same and resistance is same for both

SinCe

$R=\frac{\rho L}{A}$

So

$\frac{R_1}{R_2} =\frac{\rho_1 *A_2 }{\rho_2 *A_1}$

$1=\frac{2.65 * d^2 }{1.72 *(1.64mm)^2}$

d= 0.8056 ×1.64 mm=1.32 mm