MHT CET · Physics · Atomic Physics
If ' \(\lambda_1\) ' and ' \(\lambda_2\) ' are the wavelengths of the first member of the Balmer and Paschen series, in hydorgen atom respectively, then the ratio of respective frequencies, \(f_1 / f_2\), is
- A 20:7
- B 27:5
- C 50:9
- D 108:7
Answer & Solution
Correct Answer
(A) 20:7
Step-by-step Solution
Detailed explanation
For Balmer series (\( n_f=2 \), \( n_i=3 \)): \( 1/\lambda_1 = R_H(1/2^2 - 1/3^2) = R_H(5/36) \). For Paschen series (\( n_f=3 \), \( n_i=4 \)): \( 1/\lambda_2 = R_H(1/3^2 - 1/4^2) = R_H(7/144) \).
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