Which of the following statements regarding spectral series is correct ?

Options

A. The lines in the Balmer series corresponds to the electronic transition from higher energy level to n = 1 energy level.
B. Paschen series appears in the infra-red region
C. The lines of Lyman series appear in the visible region
D. Transition from higher energy level to 4th energy level produces Pfund series which fall in the infrared region.

Answer

To determine which statement regarding spectral series is correct, let's analyze each statement step by step.

### Step 1: Analyze the First Statement
**Statement:** The lines in the Balmer series correspond to the electronic transition from a higher energy level to n = 1 energy level.

**Analysis:**
The Balmer series involves electronic transitions that occur from higher energy levels (n ≥ 3) to n = 2. Therefore, this statement is incorrect.

### Step 2: Analyze the Second Statement
**Statement:** The Paschen series appears in the IR region.

**Analysis:**
The Paschen series consists of transitions from higher energy levels to n = 3, and it indeed falls within the infrared (IR) region of the electromagnetic spectrum. Therefore, this statement is correct.

### Step 3: Analyze the Third Statement
**Statement:** The lines of the Lyman series appear in the visible region.

**Analysis:**
The Lyman series involves transitions from higher energy levels to n = 1 and falls in the ultraviolet (UV) region, not the visible region. Therefore, this statement is incorrect.

### Step 4: Analyze the Fourth Statement
**Statement:** Transition from a higher energy level to the fourth energy level produces the Pfund series, which falls in the IR region.

**Analysis:**
The Pfund series consists of transitions from higher energy levels to n = 5, not n = 4. Therefore, this statement is incorrect.

### Conclusion
After analyzing all statements, the only correct statement is the second one: "The Paschen series appears in the IR region."

### Final Answer
The correct statement regarding spectral series is: **The Paschen series appears in the IR region.**

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