Question

The following transitions lead to the two components of sodium yellow line. The ratio of intensities of the two lines \(b\) and \(a\), \(I_b : I_a\), is:

• A. \( 1:2 \)
• B. \( 2:1 \)
• C. \( 3:2 \)
• D. \( 2:3 \)

Hint:

The intensity ratio of fine structure doublets follows statistical weights of initial states.

Answer 1

The Correct Option is C

The sodium D-lines (\(D_1\) and \(D_2\)) arise from the transitions:
\[ ^2P_{3/2} \rightarrow ^2S_{1/2} \quad \text{and} \quad ^2P_{1/2} \rightarrow ^2S_{1/2} \] The intensity ratio follows:
\[ I_{D_2} : I_{D_1} = 3:2 \]