Use the data in Table `3.1` to answer the following :
(a) Which among iron and mercury is a better conductor ?
(b) Which material is the best conductor ?

Explanation

(a) Iron is a better conductor than mercury as resistivity `(rho)` for iron `(10.0 xx 10^-8 Omega m)` is less than that for mercury `(94 xx 10^-8 Omega m)`.
(b) Silver is the best conductor as its resistivity `(rho)` in the least, i.e., `1.60 xx 10^-8 Omega m`.