在半径为R的球体内,电荷分布是球对称的,电荷体密度为ρ=ar(0≤r≤R),ρ=0( 发布时间:2017-08-17 13:29 │ 来源:www.tikuol.com 题型:单项选择题 问题: 在半径为R的球体内,电荷分布是球对称的,电荷体密度为ρ=ar(0≤r≤R),ρ=0(r>R),其中a为大于0的常数,在球体内部,距球心为x处的电场强度为()。A.B.C.D.
题型:单项选择题 Lucy couldn’t remember when she met Tom, but she was sure it was on ______Monday when she had ______ music class. A./; theB.the; /C.a; aD./; a 查看答案