單項選擇題The sub-multiple prefix "milli" (m) means （）.

A.one thousandth (10 to the -3rd power)
B.one millionth ( 10 to the -6th power)
C.one billionth ( 10 to the -9th power)
D.one trillionth (10 to the -12th power)


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1.單項選擇題A “dead front” switchboard is one （）.

A.without switches on it
B.with insulated switches and no exposed terminals
C.without circuit breakers
D.without safety hand nails nor rubber mats

2.單項選擇題The total resistance of a parallel circuit is always （）.

A.larger than the greatest branch resistance
B.smaller than the lowest branch resistance
C.equal to the sum of the individual branch resistances
D.one-half the sum of the individual branch resistances

3.單項選擇題Reduced voltage applied to a motor during the starting period will （）.

A.result in decreased acceleration time only
B.lower the starting current and increase accelerating time
C.cause a greater starting torque
D.increase the starting current and pump capacity

4.單項選擇題Line losses in a distribution circuit are kept to a minimum by （）.

A.adding rubber insulation conductors to the circuit
B.using higher current and lower voltage increasing the
C.number of thermal relays in the circuit
D.using higher voltage and lower current

5.單項選擇題Which of the following components are used to convert alternating current produced in the generator windings to direct current?（）

A.Armature and equalizer
B.Commutator and brushes
C.Rotor and interpoles
D.Field and exciter