Project wk:calculate width of spectral line

In summary, the project involves observing the sodium doublet and calculating the solar rotation speed by measuring the shift in the lines. The equations for finding the width of the lines, such as FWHM and 1/f, have been attempted but with no success. The known values are the wavelengths of the lines, the angle of the diffraction grating, and the focal length from the grating to the CCD detector. The next step is to find the width in units such as meters, nanometers, or millimeters, and then convert it to pixels on the CCD.
  • #1
indie452
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Homework Statement



for my solar rotation prodject i am observing the sodium doublet and seeing how much it shifts from either side of the sun to calculate the rotating speed

i need to calculate the predicted width of one of the sodium lines, I've tried to find the width to the minima's and also tried to find the FWHM but the equations won't work

Homework Equations



line 1 = 588.997nm
line 2 = 589.594nm
diffraction grating angle a =20.70714degrees
focal length ie distance from grating to CCD detector = 3.405m

I just need help getting the width in m/nm/mm/etc... and then i can convert it to pixels on the CCD
 
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  • #2
The Attempt at a SolutionI've been trying to use the equation for FWHM(full width half max) = 2L*sin(a/2) but the answer comes out to be 0.0032778m which is obviously wrong. I've also tried using 1/f = m(lambda) but i can't figure it out.
 

Related to Project wk:calculate width of spectral line

1. What is the purpose of calculating the width of a spectral line?

The width of a spectral line can provide valuable information about the physical properties of a substance, such as its temperature, density, and chemical composition. It can also help identify the source of the line, whether it is from a natural or artificial source.

2. What factors affect the width of a spectral line?

The width of a spectral line can be affected by several factors, including the temperature of the substance, the density of the substance, the pressure of the surrounding environment, and the speed at which the substance is moving.

3. How do scientists measure the width of a spectral line?

Scientists use a technique called spectroscopy to measure the width of a spectral line. This involves passing light through a substance and analyzing the resulting spectrum to determine the width of the lines present.

4. What are some applications of calculating the width of a spectral line?

The calculation of spectral line width has many applications in various fields such as astronomy, chemistry, and materials science. It can help identify chemical elements, determine the temperature and density of stars, and even detect pollutants in the atmosphere.

5. Are there any limitations to calculating the width of a spectral line?

There are some limitations to calculating the width of a spectral line. Factors such as the quality of the instrument used, the complexity of the substance being analyzed, and the presence of other substances can affect the accuracy of the measurement. Additionally, the width of a spectral line can sometimes be difficult to interpret, as it can be influenced by multiple factors.

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