A metal wire of resistivity `64 xx 10^-6` ohm cm and length `198 cm` has a resistance of `7 Omega`. Calculate its radius.

Answer

`0.024 cm`

Explanation

As `R = (rho l)/(A) = (rho l)/(pi r^2), r = sqrt((rho l)/(pi R)) = sqrt(((64 xx 10^-6 Omega m)(198 cm))/(3.14 (7 Omega))) =0.024 cm`.