Answer
The excitation increases the probability of detecting the electron in a small length of the x axis near one of the well walls.
Work Step by Step
In Figure 39-6, we can see that the graph of the probability density for $n = 1$ (the ground state) has a peak near the center and decreases to zero near the walls. This shows that there is a low probability of finding the electron near the walls.
The graph of the probability density for $n = 2$ (first excited state) has a trough near the center, but it has a peak closer to each wall. This shows that there is a low probability of finding the electron near the center of the well and a higher probability of finding the electron nearer the walls.
Therefore, the excitation increases the probability of detecting the electron in a small length of the x axis near one of the well walls.
