Question

an electric bulb is marked 40 W and 120 V it means that in one second it converts

Answer 1

Metals which do not become superconducting usually exhibit resistivity proportional to T2 close to zero temperature (due to electron-electron scattering which dominates over electron-phonon scattering at low enough temperature; see: Fermi liquid theory).  Extrapolating to zero temperature yields a finite intercept whose value is determined by impurity scattering--how dirty the material is.  Thus, a perfect metal with no impurities and no defects will be a perfect conductor at zero temperature (which is a distinct animal from a superconductor), but such an object doesn't exist in the real world.