What are the definition of each types of spectrum ?
What are the definition of each types of spectrum ?
What a prism does is spread light out by wavelength into a spectrum. The shortest wavelengths of visible light – violet – appear at one side of the spectrum and the longest wavelengths – deep red – appear at the other end.
Studying the light from stars and other sources is a central concern in astronomy. There is a lot that can be learned by looking at how much light is detected at each wavelength. Most light sources can be classified into three main types: continuous, absorption, and emission.
A hot, opaque object, like the filament in an incandescent light bulb, emits a continuous spectrum, having light of all wavelengths. A hot, dense gas is another example of an object that emits a continuous spectrum.
If light from a continuous spectrum passes through a cool, transparent gas we observe dark lines appear in the spectrum. The lines occur where atoms of the gas have absorbed specific wavelengths of light. Hence we call this type of spectrum an absorption spectrum.
If we view this transparent gas against a black background we would see that it also emits light (if it has an enough energy), giving an emission spectrum. An emission spectrum looks like the opposite of an absorption spectrum, with emission lines at specific wavelengths. In fact, the wavelengths of the emission lines are the same as the absorption lines (for the same type of gas). These discrete lines are due to the quantum nature of the atom. Florescent lights, neon signs, and many streetlights are examples of emission spectrum sources.
What a prism does is spread light out by wavelength into a spectrum. The shortest wavelengths of visible light – violet – appear at one side of the spectrum and the longest wavelengths – deep red – appear at the other end.
Studying the light from stars and other sources is a central concern in astronomy. There is a lot that can be learned by looking at how much light is detected at each wavelength. Most light sources can be classified into three main types: continuous, absorption, and emission.
A hot, opaque object, like the filament in an incandescent light bulb, emits a continuous spectrum, having light of all wavelengths. A hot, dense gas is another example of an object that emits a continuous spectrum.
If light from a continuous spectrum passes through a cool, transparent gas we observe dark lines appear in the spectrum. The lines occur where atoms of the gas have absorbed specific wavelengths of light. Hence we call this type of spectrum an absorption spectrum.
If we view this transparent gas against a black background we would see that it also emits light (if it has an enough energy), giving an emission spectrum. An emission spectrum looks like the opposite of an absorption spectrum, with emission lines at specific wavelengths. In fact, the wavelengths of the emission lines are the same as the absorption lines (for the same type of gas). These discrete lines are due to the quantum nature of the atom. Florescent lights, neon signs, and many streetlights are examples of emission spectrum sources.
