Question

What is the shortest wavelength present in the Paschen series of spectral lines?

Answer 1

\(\frac{1}{λ}= R_H\Big[\frac{1}{n_1^2}-\frac{1}{n_2^2}\Big]\)

For Paschen series, n₁ = 3 and n₂ = ∞

∴ \(\frac{1}{λ}= R_H\Big[\frac{1}{3^2}-\frac{1}{∞}\Big]\)= \(\frac{R_H}{9}\)

or  λ = \( \frac{9}{R_H}\) = \(\frac{9}{1.097\times10^{-7}}\) = 8.2 x 10^-7m

= 820 nm