If a dicharge is passed a glass tube containing h2 gas at a low pressure some hydrogen atom h are formed, which emit (pink- violet) in the visible region . this light can be studied with a spectrometer and is found to comprise a series of line in different wavelengths. four lines can be seen by eye but many more are observed photographically in the ultraviolet region. the lines become increasingly close together as the wavelength (lambda) decreases until the continuum.. in 1885, Ballmer showed that the wave length v of any line in the visible spectrum of atomic hydrogen could be given by simple formulae vbar= Rh(1/2^2-1/n^2) where Rh is the rydberg constant and n has the valvalue 3, 4, 5 ,... thus giving a series of lines . this is known as ballet formula . the series of lines given by this formulae is called the ballet series which appears only in the visible region of the electromagnetic spectrum

Line Spectrum of Hydrogen

The line spectrum of hydrogen refers to the specific wavelengths of light emitted or absorbed by hydrogen atoms when they transition between energy levels. This phenomenon is a result of the quantized nature of energy levels in atoms, as described by the Bohr model.

Key Points:
- When an electron in a hydrogen atom moves from a higher energy level to a lower energy level, it emits a photon of light with a specific energy corresponding to the difference in energy between the two levels.
- Each transition corresponds to a specific wavelength of light, leading to the appearance of discrete lines in the spectrum.
- The line spectrum of hydrogen is characterized by a series of lines in the visible, ultraviolet, and infrared regions of the electromagnetic spectrum.
- The most prominent lines in the hydrogen spectrum are the Balmer series in the visible region, the Lyman series in the ultraviolet region, and the Paschen series in the infrared region.
- These spectral lines are unique to hydrogen and are used to identify the presence of hydrogen in astronomical objects, such as stars and galaxies.

In conclusion, the line spectrum of hydrogen provides valuable information about the energy levels and transitions of hydrogen atoms, helping scientists understand the behavior of atoms at the microscopic level.