一半径为R均匀带电圆环带有Q电量,则圆环圆心处电场强度大小为（）V/m

A .https://assets.asklib.com/psource/99141448007128127.png B .https://assets.asklib.com/psource/10661448007138025.png C .https://assets.asklib.com/psource/81411448007150566.png D .https://assets.asklib.com/psource/64941448007162321.png

A .https://assets.asklib.com/psource/2016030208533366075.jpg B .https://assets.asklib.com/psource/201603020854028220.jpg C .https://assets.asklib.com/psource/2016030208541882638.jpg D .https://assets.asklib.com/psource/2016030208543534150.jpg

A .https://assets.asklib.com/psource/2015110114055459111.jpg B .https://assets.asklib.com/psource/2015110114060858725.jpg C .https://assets.asklib.com/psource/2015110114062064666.jpg D .https://assets.asklib.com/psource/2015110114063237571.jpg

如图所示,半径为R,电荷线密度为λ(λ>0)的均匀带电圆环,绕圆心且与圆平面垂直的轴以角速度ω转动,求: (1) 圆心O处的磁感应强度B0; (2)轴线上距圆心为a处的一点的磁感应强度B的大小和方向。 <img src='https://img2.soutiyun.com/ask/2020-05-26/95935280876753.png' />

<img src='https://img2.soutiyun.com/ask/uploadfile/10008001-10011000/f127c18291fa0ae3899c25c0bb345b98.jpg' />

A．<img src='https://img2.soutiyun.com/ask/uploadfile/5703001-5706000/c9dc2e90dc8ed7ac943863ed94862e91.jpg' /> B．<img src='https://img2.soutiyun.com/ask/uploadfile/5703001-5706000/88f920aa2c76dde97815a4dd8e98d367.jpg' /> C．<img src='https://img2.soutiyun.com/ask/uploadfile/5703001-5706000/be6f989c5f489498d753459ddb877151.jpg' /> D．<img src='https://img2.soutiyun.com/ask/uploadfile/5703001-5706000/3e8f05ddc1d95a3695ff54213d208db7.jpg' />

如图 5-44(a)所示,半径为R的均勾带电球面,带有电荷Q,沿某一半径方向上有一均匀带电细线，电荷线密度为<img src='https://img2.soutiyun.com/shangxueba/ask/65109001-65112000/65111975/957108555344651.png' />,长度为I,细线左端离球心距离为a.设球和线上的电荷分布不受相互作用影响,试求细线所受球面电荷的电场力和细线在该电场中的电势能(设无穷远处的电势为零)。 <img src='https://img2.soutiyun.com/ask/2020-04-30/95710856405086.png' />

一半径为R的帮有一缺口的细圆环,缺口长度为d(d<<r),环上均匀带有正电,电荷为q,如图5-55所示。则圆心o处的场强大小e=_____________，场强方向为_____________。 <img src='https://img2.soutiyun.com/ask/2020-04-30/957114497579253.png' />

<img src='https://img2.soutiyun.com/ask/2020-07-01/962459710924663.png' />

A、小球带正电 B、P点的电势为 C、电场的电场强度大小为 D、O、C两点间的距离为

设有半径为r的半圆形导线,均匀带电,电荷密度为<img src='https://img2.soutiyun.com/ask/2020-11-30/975597671708271.png' />,在圆心处有一单位正电荷,试求它们之间作用力的大小.

<img src='https://img2.soutiyun.com/ask/2020-04-21/956328775597827.png' />

<img src='https://img2.soutiyun.com/ask/2020-11-09/973806805768531.png' />

<img src='https://img2.soutiyun.com/ask/2020-07-22/964281249714169.png' /> A、<img src='https://img2.soutiyun.com/ask/2020-07-22/96428126108882.png' /> B、<img src='https://img2.soutiyun.com/ask/2020-07-22/96428127157442.png' /> C、<img src='https://img2.soutiyun.com/ask/2020-07-22/964281285841236.png' /> D、<img src='https://img2.soutiyun.com/ask/2020-07-22/964281300748088.png' />