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What wavelength is the peak absorbance of cobalt chloride?
510 nm
How do you quantitatively measure the colour intensities of different solutions?
This is kind of a tricky question. But if you're wanting to skip to the end, the answer is spectrophotometry. Remember that, when we speak of the intensity of a color, we are talking about the intensity of some beam of light. This intensity is just a measure of the energy deposited by this beam of light on a given area in a given time (normally measured in watts per meter squared). The problem is, when we speak of the "intensity" of the color of a solution, we use "intensity" in its colloquial sense. This "intensity" actually arises from the solution ABSORBING light. Solutions will absorb particular wavelengths of light much more than they will other wavelengths of light. Let's introduce some terms, the definition of which will become clear from the upcoming context. We have some color: A and its complementary color: B Let's say that a solution appears to be A-colored. This is because light passes through the solution, and the solution very effectively absorbs B-colored light. The extent to which the solution absorbs this B-colored light (or the absorbance) depends on the concentration of the solution, and the amount of the solution through which the light travels (path length). these relationships are governed by the Beer-Lambert Law, which is as follows. A=ebc with variables: A=absorbance (unitless) b=path length (units of length) c = concentration and e=extinction coefficient. (normally units of 1/length * concentration) The extinction coefficient is experimentally determined for a given solution at a given wavelength. Spectrophotomers are machines that find the wavelength of peak absorbance and measure that absorbance. They don't come cheap, but you can probably see why this is such an extremely powerful tool.
Relationship between color and lambda max?
We can see color in the visible region of the spectrum (400-700 nanometers). If the light absorbed by something is visible, this absorption results in the COMPLIMENT of that color being seen by the human eye. For instance: if the wavelength is 400-424 nanometers, purple is absorbed, and the compliment (opposite) of it is yellow, so you see something that absorbs wavelengths 400-424 nanometers as YELLOW. When you plot value of light absorbed (Y-axis) vs. Wavelength of incident light (X-axis), lambda max is the tallest peak on the graph, explained: let's say that highest peak is at wavelength of 532, this means that most of the light absorbed is of wavelength=532 nanometers, which is green... the complimentary color to green is red... therefore, your eye will see red, not green.
Why holmium oxide is used in calibration of uv?
Because Only holmium can give sharp peaks in both UV and Vis range, Sharp peak is very rare in UV/Vis spectroscopy. It is very stable and doesn't absorb light at lower wavelength.
Why caffeine is used in calibration of hplc?
it is retained to a lesser extent....has dual wavelength detection (245nm, 350nm) and gives a sharp and consistent peak.
What wavelength is the peak absorbance of cobalt chloride?
510 nm
Why do you use the wavelength with the maximum absorbance in spectroscopy?
Short answer:Using the maximum wavelength gives us the best results. This is because at the peak absorbance, the absobance strength of light will be at the highest and rate of change in absorbance with wavelength will be the smallest. Measurements made at the peak absorbance will have the smallest error.Long answer: It really depends on what is the largest source of error. Taking the readings at the peak maximum is best at low absorbance, because it gives the best signal-to-noise ratio, which improves the precision of measurement. If the dominant source of noise is photon noise, the precision of absorbance measurement is theoretically best when the absorbance is near 1.0. So if the peak absorbance is below 1.0, then using the peak wavelength is best, but if the peak absorbance is well above 1.0, you might be better off using another wavelength where the absorbance is closer to 1. Another issue is calibration curve non-linearity, which can result in curve-fitting errors. The non-linearity caused by polychromatic light is minimized if you take readings at either a peak maximum or a minimum, because the absorbance change with wavelength is the smallest at those wavelengths. On the other hand, using the maximum increases the calibration curve non-linearity caused by stray light. Very high absorbances cause two problems: the precision of measurement is poor because the transmitted intensity is so low, and the calibration curve linearity is poor due to stray light. The effect of stray light can be reduced by taking the readings at awavelength where the absorbance is lower or by using a non-linear calibration curve fitting technique. Finally, if spectral interferences are a problem, the best measurement wavelength may be the one that minimizes the relative contribution of spectral interferences (which may or may not be the peak maximum). In any case, don't forget: whatever wavelength you use, you have to use the exact same wavelength for all the standards and samples. See http://terpconnect.umd.edu/~toh/models/BeersLaw.htmlTom O'HaverProfessor Emeritus
What is important about the peak wavelength of a thermal radiation spectrum?
The peak wavelength, is connected to the temperature of the objects. we have short peak wavelength when the temperature is high.
What is the peak to peak distance of a wave?
The wavelength.
What is the peak to peak distance of wave?
The wavelength.
How do you label a wavelength?
you label a wavelength with amplitude, wavelength, through, and peak.
What are the four parts of a wavelength?
the four parts of a wavelength are the peak, trough, wavelength, and the amplitude.
What is described by the wavelength of wave?
The distance from on peak to the next peak
Is the wavelength the distance from the crest to trough?
The peak-to-peak amplitude is the distance from the trough to the crest. The wavelength is the distance from one crest to the next crest.
What is meant by the term wavelength?
Wavelength is the distance between the crests in waves. It is also the distance between one peak of a wave to the next corresponding peak.
The distance between one crest or peak of a sound wave and the next crest or peak?
Wavelength
What trait of wave is described by its wavelength?
The distance from one wave peak to the next wave peak
