# Tag Info

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Why is W/m2 divided by nano meters on the Y-axis. Irradiance is flux per area, or normally $W/m^2$. To get spectral irradiance, we want to know the irradiance per range of wavelengths and divide by that range. The difference between this and your value is that this form shows the intensity (how bright is the light). Your value (energy per wavelength) ...

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There's a semiclassical way of deriving the Hamiltonian term corresponding to the spin orbit interaction in an atom, but I don't know if this is what you're looking for (the correct way would be using the relativistic correction included in Dirac's equation), anyhow: Consider the classical picture of an atom orbiting the nucleus, now in the electron's ...

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The hydrogen discharge tubes typically used in student labs are not designed for long-term use. After a couple of years, the tubes leak and air gets mixed with the hydrogen. This causes them to get dim and the weaker lines are almost impossible to see. It has nothing to do with the power supply and everything to do with how new the tube it and how many ...

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Just wanted to summarize my comments: Are you sure that it is Germanium-72? Actually, it is a stable isotope and it should not have any decay mode. Can you please tell us which table you are using to search for radionuclides? There is also Mn-54 which emits 834 keV gamma radiation, but it is relatively unstable so I doubt that it's easy to find its presence ...

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Are spectra (both fluorescence and absorbance) of any molecule dependent on temperature? The characteristic wavelengths do not change with temperature but the intensities will. As temperature changes, the relative concentrations of molecules with particular energy levels will change and that will affect the relative strength of absorption bands and the ...

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The current data release is DR12. As to how to interact with the data, it depends somewhat on what you want to do. If you have small queries, for instance if you want data for only a handful of objects, there are a couple of web interfaces. If you have larger queries in mind, CASJobs is a good place to start. You'll inevitably need the schema browser to know ...

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As a rule of thumb, the uncertainty in the frequency distribution is the reciprocal of the total measurement time, or $$\Delta f \Delta T \approx 1$$ The exact constant will depend on how exactly you want to specify terms like "uncertainty in the frequency distribution". Here we can see the distance between the individual points in the frequency domain ...

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The main purpose of microscopy is to observe things that cannot be or are hardly observed by naked eye. To justify the purpose one can utilize everything that suits the purpose. For example, it can be different light paths coming from different parts of a sample or different reflection from different parts of a sample etc. Or in terms of AFM it can be ...

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One of the routine methods for detecting the presence of chemical compounds is infrared spectroscopy, and you'll find infrared spectrometers scattered around any terrestrial orgganic chemistry lab. Organic compounds absorb infrared light at characteristic frequencies, and those absorption lines can be used as a fingerprint to detect the molecule. Exactly ...

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There is something that people used to build in the olden days called a crystal radio. Out on the farms, they didn't have electricity and they couldn't afford batteries, so they found a way of listening to the radio without plugging anything in. Essentially, they were absorbing power from the transmitting station to drive their little earphone speaker. If ...

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