Which rule describes the relationship between electric current and magnetic field lines?

The right-hand rule describes the relationship between electric current and magnetic field lines effectively. According to this rule, if you point your thumb in the direction of the conventional current (the flow of positive charge) through a conductor, your fingers will curl in the direction of the magnetic field lines that are created around that conductor. This rule helps visualize how electric currents generate magnetic fields, which is fundamental in understanding electromagnetism.

In contrast, the left-hand rule is used for motors, connecting the direction of the magnetic field, current, and force acting on a conductor in a magnetic field, but it does not specifically address the relationship of current to magnetic lines of force itself. Fleming's right-hand rule is similar, but it focuses on generators and the relationship between motion, magnetic field, and current, which is slightly different from what the question seeks. Lastly, Faraday's law pertains to electromagnetic induction and describes how a change in magnetic field can induce an electromotive force (emf) in a circuit, which does not directly address the current to magnetic field relationship as established by the right-hand rule.