Question

A wire 2 m long, 0.1 mm in diameter and has resistance of 20 ohm. Calculate the resistivityof its material.

Answer 1

R=
`(pL)/(A)`

R-resistance
p-resistivity [Ohm*m]
A-cross sectional area
L-length
R=20 Ohm
l=2m
A=
`\pi r^(2)`=
`\pi (0,01)^(2) =0,000314 cm^(2)`=0,314*
`10^(-7)`m²
p=
`(R*A)/(L)`
p=
`(20*0,314*10^(-7))/(2)`=0,000000314 Ohm*m