First, take the case in the elevator is on the ground floor of some building and completely addressed.

首先我们来看看电梯,在一楼时候的情况

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So, if, for example, we were looking at a hydrogen atom in the case where we have the n equals 1 state, so the electron is in that ground state, the ionization energy, it makes sense, is going to be the difference between the ground state and the energy it takes to be a free electron.

电离氢原子所需要的能量,如果我们看n等于1的情况,电子在基态，那电离能，很合理的就是基态,和自由电子态的能量差。

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