Question

What is the wavelength (in nm) of the least energetic spectral line in the visible series of the H atom?

Answer 1

Answer:

Brackett Series (n = 4)

Explanation:

The least energetic line of Hydrogen atom lies in Brackett Series when n = 4 because these are least energetic, have longer wavelengths and lies in Infrared region of spectrum.  No traces of Pfund series are formed by H=atoms.