You have a new summer job with NASA and are working on astronomical observations using electromagnetic radiation that is not in the visible range. Your supervisor has explained 21cm radiation….

## Identify the region of the electromagnetic spectrum to which this wavelength belongs.

In Problem 14, we find that the particle in a box is not a good model for the electron in a hydrogen atom. As it turns out, the particle in a box is a reasonable first approximation for a model for the protons in the nucleus. Work with your group to show this as follows. Imagine a proton confined in an infinitely high square well of length 10.0 fm, a typical nuclear diameter. Assuming the proton makes a transition from the n = 2 state to the ground state, calculate (a) the energy and (b) the wavelength of the emitted photon. (c) Identify the region of the electromagnetic spectrum to which this wavelength belongs.