Which process allows an alternator to produce more voltage at higher RPMs?

The ability of an alternator to produce more voltage at higher RPMs is primarily due to increased rotor speed. As the alternator spins faster, the magnetic field generated by the rotor moves more quickly relative to the stator windings. This enhanced motion increases the rate of magnetic flux change, which according to Faraday's law of electromagnetic induction, leads to a higher induced voltage output. This is a fundamental principle of how alternators work: the faster the rotor turns, the more electrical energy is produced.

Other options, while related to the functioning of the alternator, do not directly influence its ability to generate more voltage as RPM increases. Increased friction generally leads to energy loss rather than enhanced output, decreased battery load pertains to the demand on the alternator rather than its output capacity, and increased electrical resistance would actually reduce the efficiency and effectiveness of voltage transmission rather than contribute positively to voltage output.