The magnetic field strength around a conductor is at its maximum when the AC current is at which degree?

The magnetic field strength around a conductor carrying alternating current (AC) reaches its maximum when the current waveform is at 90 degrees. This is due to the nature of AC, which varies in a sinusoidal pattern.

At 90 degrees in the AC cycle, the current is at its peak positive value, meaning it is delivering maximum current through the conductor. According to Ampère's Law, the strength of the magnetic field is directly proportional to the amount of current flowing through the conductor. Consequently, during this phase, the magnetic field generated by the current is at its strongest.

As the phase continues to progress beyond 90 degrees (to, for instance, 180 degrees), the current begins to decrease to zero, and the magnetic field strength subsequently diminishes. At 0 degrees, the current is also at zero after completing a full cycle, contributing to a minimal magnetic field at that point as well. Thus, the maximum field strength occurs specifically at 90 degrees when the current is at its peak.