Answer:

The correct answer is option B: Paschen series is a line spectrum in the infrared.

Explanation:

To understand this, let's first discuss what spectral series are and how they relate to the hydrogen atom.

In atomic physics, spectral series are collections of closely spaced electromagnetic radiation (light) emitted by atoms when electrons transition between different energy levels. These transitions result in the emission of photons with specific energies, which correspond to specific wavelengths or frequencies of light.

The spectral series of hydrogen is particularly important because it was one of the first examples that could be explained by quantum mechanics. The spectral series of hydrogen includes the Lyman series, Balmer series, Paschen series, Brackett series, and Pfund series. Each series is characterized by the region of the electromagnetic spectrum in which the emitted light falls.

Spectral Series of Hydrogen:

1. Lyman series: It corresponds to electron transitions from higher energy levels to the n=1 energy level. The emitted light falls in the ultraviolet region of the electromagnetic spectrum.

2. Balmer series: It corresponds to electron transitions from higher energy levels to the n=2 energy level. The emitted light falls in the visible region of the electromagnetic spectrum, specifically in the red, blue, and violet regions.

3. Paschen series: It corresponds to electron transitions from higher energy levels to the n=3 energy level. The emitted light falls in the infrared region of the electromagnetic spectrum.

4. Brackett series: It corresponds to electron transitions from higher energy levels to the n=4 energy level. The emitted light falls in the infrared region of the electromagnetic spectrum.

5. Pfund series: It corresponds to electron transitions from higher energy levels to the n=5 energy level. The emitted light falls in the infrared region of the electromagnetic spectrum.

Conclusion:

In conclusion, the statement that Paschen series is a line spectrum in the infrared is correct. The Paschen series corresponds to electron transitions in the hydrogen atom that result in the emission of light in the infrared region of the electromagnetic spectrum.

Here. I will be giving reasons option wise. so that you may know why is that not correct.

A) Given, Lyman series is a continuous spectrum. It is false. because Balmer series is continuous spectrum as it lies in visible region.

B) Yes, this is correct because :-

Balmer series lies in visible region
Paschen in infrared.

C) Balmer series is a line spectrum in visible region not ultraviolet.

D) The spectrum series formula is no where related to Rutherford as we all know what Rutherford model .