The fact that the conductance of some metals rises to infinity at some temperature below a few Kelvin is called

Wires $P$ and $Q$ have the same resistance at ordinary (room) temperature. When heated,the resistance of $P$ increases and that of $Q$ decreases. We conclude that:

$A$ copper wire is stretched to increase its length by $0.1\%$. What is the percentage increase in the resistance of the wire (in $\%$)?

What length of the wire of specific resistance $48 \times 10^{-8} \, \Omega \, m$ is needed to make a resistance of $4.2 \, \Omega$ (in $.1$)? (Diameter of wire = $0.4 \, mm$)

Consider a wire of length $L$ with a resistance of $5 \Omega$. Applying an external force,the wire is elongated such that its length becomes $3 L$. Assuming the resistivity and density of the material remain unchanged,the resistance of the elongated wire is (in $Omega$)

The conductivity of a conductor decreases with temperature because,on heating: