由电路的参数可确定电路的功率因数,如图所示电路的功率因数最接近于()。
A.0.24
B.0.98
C.0.58
D.0.65
参考答案:A
The book Robinson Crusoe ________ on the book by Daniel Defoe is well worth ______.
A.basing, reading
B.based, being read
C.based, reading
D.to be based, to read
双缝干涉实验中,要使屏上单色光的干涉条纹之间的距离变宽,可采取以下办法:(1)________;(2)________;(3)________.为测量红光的波长,现测得屏上6条亮条纹间的距离为7.5 mm,已知双缝间的距离为0.5 mm,双缝到屏幕的距离为1 m,则此红光波长为________.