The numerical relationships described by equations are helpful because they tell us the extent to which variables might affect one another.

方程描述的数值关系是有帮助的，因为它们告诉我们变量之间相互影响的程度。

Which means that we need to multiply this equation by N, the number of loops in the coil.

这意味着我们需要将这个 等式乘以线圈中的回路数 N。