单选题One factor that determines the frequency of an alternator is the（）.Anumber of turns of wire in the armature coilBnumber of magnetic polesCstrength of the magnets usedDoutput voltage
单选题
One factor that determines the frequency of an alternator is the（）.
A
number of turns of wire in the armature coil
B
number of magnetic poles
C
strength of the magnets used
D
output voltage
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