What determines the strength of the magnetic field around a conductor?

The strength of the magnetic field around a conductor is primarily determined by the amount of current flowing through it. According to Ampère's Law, the intensity of the magnetic field created by a straight current-carrying conductor is directly proportional to the current. As current increases, the magnetic field's strength increases as well, which can be visually represented using the right-hand rule; when you hold a current-carrying wire with your right hand, your thumb pointing in the direction of the current, your fingers will curl around the wire in the direction of the magnetic field lines.

While resistance, voltage, and the length of the conductor can affect current and impact other electrical properties, they do not directly determine the strength of the magnetic field generated by the current. Resistance influences how much current can flow for a given voltage according to Ohm's Law, but it is the current itself that drives the magnetic field's strength.