Question

A copper wire of conductance 0.2 mho has length 50 cm and

radius 0.1 mm. Calculate its resistivity and conductivity.​

Answer 1

Given:- A copper wire of conductance 0.2 ohm has length 50 cm and radius 0.1 mm.

To find:- Its resistivity and conductivity

Solution:- According to the question, the length of the wire is 50cm = 0.5 meter

and radius of the wire is 0.1 mm = 0.1/1000 meter =1×10^(-4)

So, R= 0.2 A= πr²= 3.14×10^(-8) (r=radius) L = 50 cm = 0.5 meter

we know,

Resistivity = R×A/L ohm.m

= 0.2×3.14×10^(-8) / 0.5 = 1.25 × 10^(-8) ohm.m

and we know,

Conductivity = L/(R×A) ohm.m

= 0.5/ [ 0.2×3.14×10^(-8)] ohm.m

= 79.6×10^6 ohm.m

So, its resistivity and conductivity are respectively 1.25 × 10^(-8) ohm.m and 79.6×10^6 ohm.m