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AP EAMCET · PHYSICS · Atomic Physics

The ratio of longest wavelength lines in the Balmer and Paschen series of hydrogen spectrum is

  1. A \(\frac{5}{36}\)
  2. B \(\frac{7}{20}\)
  3. C \(\frac{7}{144}\)
  4. D \(\frac{5}{27}\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(\frac{7}{20}\)

Step-by-step Solution

Detailed explanation

\(\frac{1}{\lambda_{B L}}=R\left[\frac{1}{2^2}-\frac{1}{3^2}\right]=\frac{5}{36} R \Rightarrow \lambda_B=\frac{36}{5 R}\) ...(A) \(\frac{1}{\lambda_{P L}}=R\left[\frac{1}{3^2}-\frac{1}{4^2}\right]=\frac{7}{144} R \Rightarrow \lambda_P=\frac{144}{7 R}\) ...(B) On dividing Eq. (B)…