【简答题】An FM radio transmitter has a power output of 100 kW and operates at a frequency of 94 MHz. The energy of a photons is __________________. How many photons per second does the transmitter emit? ______...
【多选题】关于中国共产党历史上的重要会议,下列说法正确的是
D.
瓦窑堡会议:确定建立抗日民族统一战线的方针政策
【单选题】使用Fluke 17B数字万用表测量二极管得到的值是_____?
【单选题】某变速齿轮需在轴上频繁移动,拟采用矩形花键联接,若两联接表面硬度均大于50HRC,该联接宜采用 定心方式。
【单选题】The primary AC system is a three-phase, four-wire, wye connected system that operates at a voltage of 115/200V AC, a frequency of 400Hz and is rated at 90kVA. choose the wrong answer:
A.
the primary AC system has a three-phase generator
B.
Four wires tied the generator to the plane
D.
The rated power of the generator is 90 KVA
E.
the phase voltage is 115V
F.
the line voltage is 200V
【简答题】S7-200 系列PLC定时器分为三类,分别是____,____,____。
【简答题】Assume a two-country two-good two-input model. Let the countries in the model be the United States and the Rest of the World and the goods be steel and wheat. The two factors of production are capital...