equipotential造句
        The surface itself is an 
equipotential.
表面本身是一等位面.
Lines within the field along which the voltage is constant are called 
equipotential.
在电场中电压根等的那些曲线称为等位线.
At each crossing of an 
equipotential and a field line, the two are perpendicular.
在等位面与电力线的每个交点, 两者是垂直的.