Cacculate the resissivity of the amterial of a wire 1.0 m long, 0.4 mm in diameter and having a resistance of 2.0 ohm.

Explanation

`rho = ?`
`l = 1.0m`
Diameter = d = 0.4
Radius `= r -= d/2 = (0.4)/2 = 0.2 mm`
` r = 0.2 xx10^(-3) m`
`rho = (RA)/(l) = R/l (pir^2)`
`rho = 2/1xx22/7 xx(0.2xx10^(-3))^(2)=0.25xx10^(-6)`
`rho=2.5xx10^(-7)Omegam`