b . A spectrum in which only specific wavelengths are present is known as a line spectrum . It has bright lines with dark spaces between them .
Electromagnetic spectrum is a continuous spectrum . It consists of a range of electromagnetic radiations arranged in the order of increasing wavelengths or decreasing frequencies . It extends from radio waves to gamma rays .
Spectrum is also classified as emission and line spectrum .
o Emission spectrum : The spectrum of radiation emitted by a substance that has absorbed energy is called an emission spectrum .
o Absorption spectrum is the spectrum obtained when radiation is passed through a sample of material . The sample absorbs radiation of Certain wavelengths . The wavelengths which are absorbed are missing and come as dark lines .
The study of emission or absorption spectra is referred as spectroscopy . Spectral Lines for atomic hydrogen :
Rydberg equation
R = Rydberg ’ s constant = 109677 cm -1