一电场强度为<img src="https://zk.995w.com/lqwvjeImg/ed/edc0f0e72e59451cfc6dd821a20a781e.png" style="font-size: 20px;" >的均匀电场,<img src="https://zk.995w.com/lqwvjeImg/ed/edc0f0e72e59451cfc6dd821a20a781e.png" style="font-size: 20px;" >的方向与沿x轴正向,如图所示.则通过图中一半径为R的半球面的电场强度通量为 ( )<img src="https://zk.995w.com/lqwvjeImg/69/69cfb4d954d55650baa01d7fd961abe8.png" style="width:160px;height:107px;" ><br>·<img src="https://zk.995w.com/lqwvjeImg/93/93fb4b48941e4235ffbd593c6365d36d.png" ><br>· R2E / 2.<br>· 2R2<br>· 0.