You are given a copper wire. What is the effect of rise in temperature in the conductivity of the wire?

The conductivity of the copper wire decreases.

The resistivity of conductors is given as : \(\rho \) = \(\frac{m}{e^{2}\tau n}\). The resistivity increases with decrease in relaxation time which further decreases with rise in temperature due to increase in collision frequency.

Therefore, resistivity increases with temperature and hence conductivity of metal decreases with rise in temperature.