【简答题】How to define the specific gravity of the crude oil?
【单选题】已知某正弦交流电压的表达式为:u=220 sin628t V,则此正弦交流电压的有效值和周期分别为 :
【单选题】已知某正弦交流电压的表达式为:u=220 2 sin628t V,则此正弦交流电压的有效值和周期分别为________ 。
【单选题】已知某正弦交流电压的表达式为:u=220 2 sin628t V,则此正弦交流电压的有效值和
【单选题】_____ shows 1.2 meter and the specific gravity of the oil is 0.96According to the measuring scale, that makes 150 tons.
【单选题】______ the weight and the specific gravity of a body, you can calculate its volume.
【单选题】The specific gravity of fuel oil is a ___
【单选题】The specific gravity of fuel oil is a _____.
【单选题】我国中、小型电力系统正常运行时,规定允许频率偏差为( )Hz。
【单选题】已知某正弦交流电压:U=220V,f=50Hz,初相为60°,则其正确的瞬时表达式为( )