Question

What is the minimum wavelength in the Lyman series of the hydrogen spectrum?

• A. \(91.2\,\text{nm}\)
• B. \(121.6\,\text{nm}\)
• C. \(656.3\,\text{nm}\)
• D. \(364.6\,\text{nm}\)

Hint:

Remember the limiting wavelengths of the important hydrogen series: \[ \begin{aligned} \text{Lyman limit} &\approx 91.2\,nm,\\ \text{Balmer limit} &\approx 364.6\,nm. \end{aligned} \] The minimum wavelength of any spectral series is obtained by taking \[ \boxed{n_{2}\rightarrow\infty.} \]

Answer 1

The Correct Option is A

The minimum wavelength in the Lyman series corresponds to the transition $n = \infty \to n = 1$, releasing the maximum energy of 13.6 eV. Using $\lambda = hc/E$ gives $\lambda_{\min} \approx 912$ Å, which is the series limit.