Which of the following series of transitions in the spectrum of hydrogen atom fall in visible region?

Options

A. Paschen series
B. Brackett series
C. Lyman series
D. Balmer series.

Answer

To determine which series of transitions in the spectrum of the hydrogen atom falls in the visible region, we need to analyze the different series provided: Paschen series, Brackett series, Lyman series, and Balmer series.

### Step-by-Step Solution:

1. **Identify the Series:**
- The four series mentioned are:
- Paschen series
- Brackett series
- Lyman series
- Balmer series

2. **Understand the Regions of Spectrum:**
- Each series corresponds to transitions between energy levels in the hydrogen atom and emits light in different regions of the electromagnetic spectrum.
- **Lyman series:** Transitions from n ≥ 2 to n = 1 (ultraviolet region).
- **Balmer series:** Transitions from n ≥ 3 to n = 2 (visible region).
- **Paschen series:** Transitions from n ≥ 4 to n = 3 (infrared region).
- **Brackett series:** Transitions from n ≥ 5 to n = 4 (infrared region).

3. **Determine the Visible Region:**
- The visible region of the electromagnetic spectrum is approximately from 400 nm to 700 nm.
- The Balmer series is known to emit light in this range, specifically the wavelengths corresponding to the transitions from higher energy levels down to n = 2.

4. **Conclusion:**
- Among the given series, only the **Balmer series** falls within the visible region of the spectrum. The other series (Lyman, Paschen, and Brackett) fall outside this range (ultraviolet and infrared).

### Final Answer:
The series of transitions in the spectrum of the hydrogen atom that falls in the visible region is the **Balmer series**.