Spectra Flashcards
What is an emission line spectra?
Each element produces a unique emission line spectrum because of its unique set of energy levels
What is a continuous spectra?
All visible frequencies or wavelengths are present. The atoms of a heated solid metal will produce this type of spectrum.
What is an absorption line spectra?
This type of spectrum has series of dark spectral lines against the background of a continuous spectrum. The dark lines have exactly the same wavelengths as the bright emission spectral lines for the same gas atoms
When is an absorption line spectra formed?
When light from a source that produces a continuous spectrum passes through a cooler gas.
Why do you get an absorption spectra?
- At low temperatures, most of the electrons in the gas atoms will be in their ground states.
- Photons of the correct wavelength are absorbed by the electrons to excite them to higher energy levels.
- These wavelengths are missing from the continuous spectrum when it comes out on the other side.
- You see a continuous spectrum with black lines in it corresponding to the absorbed wavelengths.