Question

Which among iron and mercury is a better conductor of electricity?

Answer 1

Hint: the amount of current flowing through any material depends upon the resistance offered by the material. More is the resistance offered, less will be the current flowing through it. Resistance depends on various factors like length of conductor, area of cross section, resistivity and also nature of the material.

Complete step by step solution: iron is considered a better conductor of electricity in comparison with mercury. According to ohm’s law current flowing through a conductor is directly proportional to the potential applied across the conductor or the potential difference is equal to the product of current and resistance i.e. $$V = IR$$.
Also $R$ = $\dfrac{\rho l}{A}$
where =resistivity of material, l = length and A = area of cross-section of conductor.
Resistivity of mercury is $98 \times 10^{-8} ohm-m$ whereas the resistivity of iron is $1.0 \times 10^{-7} ohm-m$.

Since iron has less resistivity therefore it offers less resistance than mercury. The current flowing through a conductor is inversely proportional to the resistance offered by the conductor. Another reason for iron being a good conductor is that it is a solid and mercury is a liquid. Solid conducts electricity more than liquid. Due to the nature of materials it affects the flow of current. Both iron and mercury are metals and considered as conductors of electricity. But iron is a better conductor than mercury.

Note: The current flowing through the conductor is inversely proportional to the resistance offered. More is the resistance offered less will be the current flowing through it and vice-versa. For comparison check which conductor offers less resistivity, that metal will conduct more electricity through it.