Which of the following is false?

Options

A. Pfund spectral series for which `n_(1) = 5` and `n_(2) = 6,7…..` lies the infrared region of the electronetic radation
B. Visible region of electromagnetic radiation has wavelength from `400 nm to 800 nm`
C. Balmer spectral series lies in the visible proton of the electromagnetic radiation
D. Lyman series lies in the visible protion of the electronetic radiation

Explanation

To determine which of the statements is false regarding the spectral series of hydrogen, we will analyze each statement step by step.

### Step 1: Analyze the Pfund Series
The first statement mentions the Pfund spectral series, where \( n_1 = 5 \) and \( n_2 = 6, 7, \ldots \). The Pfund series corresponds to transitions from higher energy levels down to \( n = 5 \). It is known that the Pfund series lies in the infrared region of the electromagnetic spectrum.

**Conclusion:** This statement is **true**.

### Step 2: Analyze the Wavelength of Visible Light
The second statement claims that the visible region of electromagnetic radiation has wavelengths from 400 nanometers to 800 nanometers. This is a well-established fact in physics.

**Conclusion:** This statement is **true**.

### Step 3: Analyze the Balmer Series
The third statement states that the Balmer series lies in the visible portion of the electromagnetic radiation. The Balmer series corresponds to transitions from higher energy levels down to \( n = 2 \) and indeed falls within the visible spectrum.

**Conclusion:** This statement is **true**.

### Step 4: Analyze the Lyman Series
The fourth statement claims that the Lyman series lies in the visible portion of the electromagnetic radiation. However, the Lyman series corresponds to transitions from higher energy levels down to \( n = 1 \) and is known to be in the ultraviolet region of the electromagnetic spectrum, not the visible region.

**Conclusion:** This statement is **false**.

### Final Answer
The false statement is: **The Lyman series lies in the visible portion of electromagnetic radiation.**

---