What is the resistance of insulating materials?

How does the resistivity of alloys compare with those of pure metals from which they may have been formed?

$(a)$ Resistivity of iron is $10 \times 10^{-8} \; \Omega m$ and of mercury is $94 \times 10^{-8} \; \Omega m$. Which among iron and mercury is a better conductor? Give reason.
$(b)$ Resistivity of a material $A$ is in the range of $10^{10}-10^{14} \; \Omega m$ while that of $B$ is in the range of $10^{-6}-10^{-8} \; \Omega m$. Which of the two will behave as an insulator and why?

How are electrical appliances connected to the main line in our homes?

Why do the wires connecting an electric heater to the mains not glow while its heating element does?

Identify the circuit (Figure) in which the electrical components have been properly connected.