截面(英语:Cross section)为一几何学名词,是指一三维空间下的物体和一平面相交所产生交集。截面的面积称为截面积。
棒子的横截面积,成反比。
Inversely proportional to the cross-sectional area of the rod.
杆件的横截面积不能为零。
导体的电阻与其长度成正比,与其横截面积成反比。
The resistance of a conductor varies directly with its length, conversely with its cross-sectional area.
B is the assumed cross-section of the nucleus.
假定B是核的横截面积。
So, the number of nuclei, 119 if we were to sit and count these as well, is 119. So, we'll multiply that by just pi, r squared, to get that cross-section, and divide all of that by 1 . 39 meters squared.
如果你们数的话,原子核的数是,我们用它乘以πr的平方,得到横截面积,除以1。39平方米。
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