在静电场中，将一正电荷从a点移到b点，电场力做了负功，则( )．
A．b点的电场强度一定比a点大
B．电场线方向一定从b指向a
C．b点的电势一定比a点高
D．该电荷的动能一定减小
参考答案：C
解析： 正电荷从a点移到b点，电场力做负功，则电荷电势能增加，b点电势比a点高，选项C正确．电势高低与场强大小无关，选项A错误．b点电势比a点高，但是a、b不一定在同一条电场线上，选项B错误．电场力对电荷做负功，但电荷可能还受别的力的作用，总功不一定为负，动能不一定减小，选项D错误．
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