真空中有两个相距0.3m、带电量相等的点电荷,它们间的静电力的大小为10-3N,求每个点电荷所带电荷量是多少?(静电力常量k=9.0×109N·m2/C2)
1.0×10-7 C
清朝雍正帝维持和发展了康熙开创的盛世局面。下列史实中,发生在雍正年间的是( )
A.四大徽班进京,京剧初步形成
B.短暂开放,允许全国“一体贸易”
C.制瓷工艺提高,粉彩瓷器达鼎盛
D.设立军机处,使之独掌决策大权
_____ is the most difficult of _____. [ ]
A. Lesson Nine; Book Three
B. The lesson nine; the book three
C. The nine lesson; the three book
D. The Ninth lesson; the Third Book