对于库仑定律,下面说法正确的是( ) A 、库仑定律适用于真空中两个点电荷之间的相互作用力 B 、两个带电小球即使相距非常近,也能用库仑定律 C 、相互作用的两个点电荷,不论它们的电荷量是否相同,它们之间的库仑力大小一定相等 D 、当两个半径为r的带电中心相距为4r时,对于它们之间的静电作用力大小,只取决于它们各自所带的电荷量 A.B.C.D. D
【简答题】Advertisement is the difficult business of bringing information to great numbers of people.The purpose of an advertisement is to make people respond to make them react to an idea,such as helping preve...
【简答题】阅读理解。 Many children first learn the value of money by receiving an allowance (零用钱). The purpose is to let children learn from experience at an age when financial mistakes are not very costly. The amou...