题目

While you are online there are plenty of perfectly legal sites where you can listen to music for free. This gives you the chance to listen to music before buying it, discover new music, and create great online playlists that you can share with others. The Sixty One The Sixty One is devoted to showcasing obscure or unknown artists of all genres. There’s a range of musical styles from classical to rock and roll, folk to jazz, and everything in between. Don’t expect to find big name musicians on here; you’re more likely to find the musicians playing at local coffee shops than bands y4．在如图所示的匀强电场中，1、2、3三条虚线表示三个等势面，a、b分别是等势面1、3上的两个点．下列说法中正确的是（　　）A．三个等势面的电势相等B．等势面2的电势高于等势面1的电势C．若将一正电荷由a移到b，电场力做负功D．若将一正电荷由a移到b，电场力做正功