Question

The resistance of a copper wire 200 m long is 21Ω. If its thickness (diameter) is 0.44
mm, its specific resistance is around

Answer 1

hey mate ur answer is in the given attachment

hope it is helpful

Answer 2

Answer:

The specific resistance of the wire is 1.5972×10⁻⁸Ω-m.

Explanation:

The resistance of the wire is given as,

$R=\frac{\rho l}{A}$       (1)

Where,

R=resistance of the wire

ρ=specific resistance of the wire

l=length of the wire

A=area of the cross-section of the wire

From the question we have,

R=21Ω

Diameter=0.44× 10⁻³m

Radius=0.22× 10⁻³m

Length of the wire(l)=200m

$21=\frac{\rho \times 200}{\pi \times( 0.22\times 10^-^3)^2}$

$\rho=\frac{21\times \pi\times (0.22\times 10^-^3)^2}{200}=1.5972\times 10^-^8\Omega-m$

Hence, the specific resistance of the wire is 1.5972×10⁻⁸Ω-m.