It is found recently that the core of neutron star is in a state of superfluidity (superconductivity). How much the electric conductivity of white dwarf and neutron stars as compared to normal metals. It is also found that hydrogen at pressure of some hundreds gigpascal is transformed into metal. How much is its electric conductivity as well? Is infinite conductivity of a superconductor make sense? Physical quantities should be infinite owing to quantum mechanics principles.