In the Bohr model of the hydrogen atom, electrons are confined to orbits with fixed
radii, and those radii can be calculated. The radii of the first four orbits are 0.53,
2.12, 4.76, and 8.46 Å, respectively, as depicted in the figure below. The image on
the right shows the output of a detector that measures the intensity of light emitted
from a sample of hydrogen atoms that have been excited so that each atom begins
with an electron in the n = 4 state. What is the final state, nf, of the transition being
detected