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