Question

Emission transitions in the Paschen series end at orbit $n$ $=$ $3$ and start from orbit $n$ and can be represented as $v=3.29\times {10}^{15}\left(Hz\right)[1/3^2-1/n^2]$ Calculate the value of $n$ if the transition is observed at 1.285 nm. Find the region of the spectrum.

Answer 1

$\upsilon =c/\lambda =\frac{3\times {10}^8}{1285\times {10}^{-9}}$

and also $\upsilon =3.39\times {10}^{15}(1/3^2-1/n^2)$

$1/n^2=1/9-\frac{3\times {10}^8}{1285\times {10}^{-9}}\times \frac{1}{3.29\times {10}^{15}}$

= 0.111 - 0.071

= 0.04 or 1/25

or $n^2$ = 25

or $n=5$

and the spectrum lies in the infrared region.