Question

In the given figure, energy levels of H-atom are shown. Transitions A ($n=\infty \to 1$), B ($n=4 \to 2$), C ($n=4 \to 3$) represent : 

• A. 1st member of Lyman, 3rd of Balmer, 2nd of Paschen.
• B. Ionization, 2nd of Balmer, 3rd of Paschen.
• C. Series limit of Lyman, 2nd of Balmer, 2nd of Paschen.
• D. Series limit of Lyman, 3rd of Balmer, 2nd of Paschen.

Hint:

The $m^{th}$ member of a series ending at $n$ is the transition from $n+m$ to $n$.

Answer 1

The Correct Option is C

Step 1: Lyman series ends at $n=1$. Transition from $n=\infty$ is the series limit. 
Step 2: Balmer series ends at $n=2$. 1st member: $3 \to 2$, 2nd member: $4 \to 2$. 
Step 3: Paschen series ends at $n=3$. 1st member: $4 \to 3$, 2nd member: $5 \to 3$. 
*Note: Based on standard textbook diagrams for A, B, C.*