Question

why onlg moving charges can create magnetic field??

Answer 1

they contitutes current

Answer 2

let us consider an another aspect of this problem.....when a magnet is moved toward and away from a conductor...there is a change in magnetic flux.so a current flows through the conductor due to the potential created.thus there is a relative motion between the movement charge and the magnetic field.thus only moving charges constitute current and it can only create magnetic field.