单项选择题
A.stationary；rotate B.stationary；stationary C.rotate；stationary D.rotate；rotate
The power factor is a measure of the phase difference b...
单项选择题The power factor is a measure of the phase difference between voltage and current and is expressed as the（） of the phase angle.
A.sine B.cosine C.tangent D.cotangent
With a purely resistance load the voltage and current a...
单项选择题With a purely resistance load the voltage and current are in phase, giving a power factor of （）.
A.one B.less than one C.more than one D.negative one
The alternating current generator supplying a load has ...
单项选择题The alternating current generator supplying a load has a voltage drop resulted from the loadWhen the load has a lagging power factor this voltage drop （）.
A.is small B.may be neglected C.is useful D.is considerable
