The frequency of an alternator at a given r/min is determined by 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

A.陕西、云南、广东B.山西、广西、福建C.河北、湖南、福建D.河南、四川、广东

单项选择题

The operation of _______two alternators requires the vo...

单项选择题The operation of _______two alternators requires the voltages to be equal and also in phase

下列何者为清代叠山艺术的代表作？( )A.狮子林B.网师园C.环秀山庄D.拙政园

单项选择题下列何者为清代叠山艺术的代表作？( )