Question

Among iron and mercury which is a better conductor of electricity and why?

Answer 1

The conductivity of a substance depends on the resistivity of that substance, Low resistance implies high current flow

Resistance:

1. The opposing tendency of a substance for the flow of current through it is known as resistance, Formula: $R=\frac{\rho l}{A}$,
2. where $\rho$is resistivity, $l$ is the length of the substance, $A$ is the area of cross-section of the substance.
3. The conductivity of a substance depends on $\rho$particularly as $l$ & $A$ are in our hands to adjust.
4. low $\rho$ ⇒ low resistance ⇒ High current flow.

The value of $\rho$ of Iron is $1.0\times {10}^{-7}\Omega -m$ and that of mercury is $9.8\times {10}^{-7}\Omega -m$.

As the resistivity of iron is less than that of mercury, Iron is a better conductor of electricity.