Question 70Electricity & Electronics - QMED

The correct answer is A) by the number of magnetic poles. The frequency of an alternator at a given RPM is determined by the number of magnetic poles within the alternator. This is because the frequency is directly proportional to the number of magnetic poles and the rotational speed (RPM) of the alternator. As the alternator rotates, the magnetic fields within the alternator induce a voltage, and the frequency of this voltage is determined by the number of magnetic poles. The other options, such as the number of turns in the armature coil, the strength of the magnets, or the output voltage, do not directly determine the frequency of the alternator.