The integral of dA is A; the area of the concentric spherical surface.

dA的积分是A;同心球面的面积。

So, the electric flux is independent of the  radius of the concentric spherical surface?

那么，电通量与同心球面半径无关吗？

Actually, the electric field has the  same magnitude as it passes through every infinitesimally small area, dA, on the  concentric, spherical surface through which we are finding the flux.

实际上，当电场穿过我们正在寻找通量的同心球面上的每个无穷小区域 dA 时，它具有相同的幅度。

In the example we just did, capital  Q is the charge of the point charge, and it is the charge enclosed inside an  imaginary spherical surface and the imaginary spherical surface is called a Gaussian surface.

在我们刚才做的例子中， 大写 Q 是点电荷的电荷，它是被包裹在一个假想球面内的电荷， 这个假想球面称为高斯曲面。