两点电荷相距为d,相互作用力为F;保持两点电荷电荷量不变,改变它们之间的距离,使之相互作用力的大小变为4F,则两电荷之间的距离应变为( )A.4d B.2d C. D. 答案:C 解析:由库仑定律F=k可知,要使带电荷量保持不变而作用力增大4倍,应该使距离变为原来的一半. To all the famous artists’ surprise, the unknown woman’s two_______paintings are also on show in the art exhibition. A. littie blue oil B. blue little oil C. oil blue little D. little oil blue