- published: 26 May 2012
- views: 52652
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules from their characteristic spectral lines. These "fingerprints" can be compared to the previously collected fingerprints of atoms and molecules, and are thus used to identify the atomic and molecular components of stars and planets which would otherwise be impossible.
Spectral lines are the result of interaction between a quantum system (usually atoms, but sometimes molecules or atomic nuclei) and a single photon. When a photon has about the right amount of energy to allow a change in the energy state of the system (in the case of an atom this is usually an electron changing orbitals), the photon is absorbed. Then it will be spontaneously re-emitted, either in the same frequency as the original or in a cascade, where the sum of the energies of the photons emitted will be equal to the energy of the one absorbed (assuming the system returns to its original state).
The General Certificate of Education Advanced Level (short form: GCE Advanced Level), or more commonly, the A Level, is a school leaving qualification offered by educational bodies in the United Kingdom and the British Crown dependencies to students completing secondary or pre-university education. A number of countries, including Singapore, Kenya, Mauritius and Zimbabwe have developed qualifications with the same name as and a similar format to the British A Levels. Obtaining A Level or equivalent qualifications is generally required for university entrance.
A Levels are generally worked towards over two years and split into two parts, with one part studied in each year. The first part is known as the Advanced Subsidiary Level, A1 Level or AS Level (the AS Level acronym was previously used for the separate Advanced Supplementary Level qualification). The second part is known as the A2 Level and is more in depth and academically rigorous than the A1 Level. The AS Level is a qualification in its own right, and the AS Level combined with the A2 Level forms the complete A Level qualification. Up to June 2009 a third Special / Advanced Extension Award level was available for the brightest candidates.
A description of how different chemicals can produce very specific emission lines or absorption lines in the spectrum of light from a distant object and how each chemical element has its own unique set of spectral lines. Part of an introductory series on astronomy. Let us know what you think of these videos by filling out our short survey at http://tinyurl.com/astronomy-pulsar. Thank you!
086 - Emission and Absorption Spectra In this video Paul Andersen explains how the photons emitted from or absorbed by an atom or nuclei is directly related to electrons moving between energy level. Absorption and emission are a direct result of the conservation of energy. Scientists may use the emission spectra of material to determine the atoms or molecules contained within the material. Do you speak another language? Help me translate my videos: http://www.bozemanscience.com/translations/ Music Attribution Title: String Theory Artist: Herman Jolly http://sunsetvalley.bandcamp.com/track/string-theory All of the images are licensed under creative commons and public domain licensing: English: Colorful Spectrum simulationEspañol: Espectro de Colores de La Luz visibleEsperanto: Koloro...
This video shows the spectral lines of hydrogen atom, represented by the orbital diagram of an atom.
A look at spectral lines from different elements and molecules, and from a thermal emitter.
Why are fireworks coloured, how can we tell what elements are in stars just from the light we see? This video explains why physics is all about sunshine and rainbows. If you would like to see more A Level Physics videos then please Subscribe to my channel to keep updated with new videos and to search the Playlists already created. You can also visit my site 'A Level Physics Online' to see how all the videos relate to your course and for even more resources at http://www.alevelphysicsonline.com/ Thanks for watching, Mr Matheson
Electrons occupying the energy shells in an atom take the form of a cloud surrounding the much smaller nucleus. Since only two electrons can fit into each of the energy shells, it is interesting to look at the characteristics of these different shells or energy states. These states are defined first by a primary quantum number called “n” and also by a secondary quantum number called “l”. And for each state, the electron has a different energy, which results from the shape of the electron cloud. For n=1, called the ground state, the shape is a symmetric cloud…the same in all directions. For n=2, the shape can take on two forms depending on the value of “l” …although both shapes have the same energy… One shape is a double spherical cloud – one sphere inside the other. While the other shape f...
Joseph Fraunhofer, (ennobled in 1824 as Ritter von Fraunhofer) was a German optician. He is known for the discovery of the dark absorption lines known as Fraunhofer lines in the Sun's spectrum, and for making excellent optical glass and achromatic telescope objectives. A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from a deficiency or excess of photons in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used as a sort of "atomic fingerprint," as gases emit light at very specific frequencies when exposed to electromagnetic waves, which are displayed in the form of spectral lines. These "fingerprints" can be compared to the previously collected fingerprints of elements, and are thus used to identif...
Video lecture discussion the different types of spectra possible in astronomy.
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