Final answer:
The maximum voltage in a coil rotating in a magnetic field is generated when the conductor moves across the field at a 90-degree angle, as this position corresponds to the maximum rate of change of magnetic flux.
Step-by-step explanation:
The maximum voltage is generated by a rotating wire when the conductor is moving across a magnetic field at 90 degrees. This is because the induced electromotive force (emf) in a coil that is rotating in a magnetic field will be at a maximum when the change in magnetic flux is at a maximum.
Induced emf is governed by Faraday's Law of Electromagnetic Induction, which states that the emf induced in a circuit is directly proportional to the rate of change of magnetic flux through the circuit. The maximum rate of change of magnetic flux occurs when the coil moves from a position parallel to the magnetic field lines to one that is perpendicular, or vice versa, which corresponds to the coil moving through the field at a 90-degree angle.