题目内容 (请给出正确答案) 提问人:网友 发布时间: 【简答题】 如图所示,半径为a,带正电荷且线密度是λ(常量)的半圆,以角速度ω绕轴O′O″匀速旋转。求: <br /> (1)O点的<img src="https://nimg.ppkao.com/2019-05/wangjing/2019050916483043733.jpg?sign=e193e008514a1e44392306960e025a14&t=62d5a5b8" />;  <br /> (2)旋转的带电半圆的磁矩<img src="https://nimg.ppkao.com/2019-05/wangjing/2019050916481443729.jpg?sign=b4f26ae0adf57b3efceb84ca5d613e53&t=62d5a5b8" /><img src="https://nimg.ppkao.com/2019-05/wangjing/2019050916485596182.jpg?sign=3628f56b6a222f2686e4052a65439cd8&t=62d5a5b8" /><br /> <img src="https://nimg.ppkao.com/2019-05/wangjing/2019050916484312821.jpg?sign=8166bd1c408e7bbfe18bb8b060eeccad&t=62d5a5b8" /> 查看正确答案