乳房炎是由()侵入乳腺组织而引起的 ["A.细菌","B.病毒","C.消毒药"]
RLC串联电路于谐振时,其电路阻抗大小为何?() ["比电路电阻大","大约等于电容电抗","大约等于电感电抗","大约等于电路电阻"]
一正弦波电压的有效值为34伏特,其峰值电压为何?() ["123伏特","96伏特","55伏特","48伏特"]
将硼元素掺进硅晶体内,则成为何种半导体?() ["N型","P型","本质型半导体","NPN型"]
新投运电容器组应进行()合闸冲击试验。 ["A.3次","B.5次","C.7次","D.1次"]
精液稀释的目的是什么?