It's a standard question on the atomic emission spectrum.
An atomic emission spectrum of hydrogen shows three wavelengths: 1875 nm, 1282 nm, and 1093 nm. Assign this wavelengths to transitions in the hydrogen atom.
I understand how to calculate it, but from both the answers in my book and the answer from slader.com. Both just say
since these wavelengths are larger than those of visible light, then we assume $n_\mathrm{f} = 3.$
However, I don't understand why we could assume $n_\mathrm{f} = 3.$ Is it because we just look at Paschen series (Bohr series, $n′ = 3$) and the Paschen lines all lie in the infrared band? Could anyone explain it?
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