Estimate diffraction angle - homemade spectrometer

In summary, the task is to estimate the diffraction angle using the spectrometer made from rolling up a 30cm long piece of cardboard into a tube, with duct tape over one end and a thin slit on the other end with a diffraction grating. Through the diffraction grating, the slit and 8 spectra can be seen, forming a pattern similar to a square. The equation ΔΘ=2λ/b is suggested for estimating the diffraction angle, but it may not be accurate due to potential errors in estimating the slit width and the wavelength of white light. It is also questioned if looking through the tube is the intended way to use the spectrometer, and it is suggested to compare the spectrometer to the one
  • #1
Jon.G
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Homework Statement


Estimate the diffraction angle.
The spectrometer is made from rolling up a 30cm long piece of cardboard into a tube. Duct tape is placed over one end, and a thin slit is made. The other end has a diffraction grating held in place.
I look through the diffraction grating and can see the slit and 8 spectra, going away from the slit. (as if there's one at each corner and halfway along each side of a square)

Homework Equations


ΔΘ=2λ/b for b>>λ
b is slit width

The Attempt at a Solution


I'm not sure if there's another way to do this.
Using this equation, I'd just be taking estimates that could be way off for the slit width and the wavelength (just using white light).
But then the task does say to estimate, so it could be ok.

Thanks for your time.
 
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  • #2
If your diffraction grating has slits, I don't see how you get the pattern you described.
Are you sure that you looking through the tube is the intended way to use the spectrometer?
 
  • #3
Does your spectrometer look something like the one described here ?
 

1. How does a homemade spectrometer work?

A homemade spectrometer uses a diffraction grating to separate light into different wavelengths. The diffraction grating is a surface with a series of parallel lines that act as tiny prisms, causing the light to bend and separate. By measuring the angle at which the different wavelengths of light are diffracted, the spectrometer can estimate the diffraction angle.

2. What materials do I need to build a homemade spectrometer?

The materials needed to build a homemade spectrometer include a diffraction grating, a light source, a slit or narrow opening to let light into the spectrometer, a screen or surface to project the diffracted light onto, and a protractor or angle-measuring tool.

3. Can I use a homemade spectrometer for accurate measurements?

While a homemade spectrometer may not be as precise as a professional spectrometer, it can still provide relatively accurate estimates of diffraction angles. This can be useful for simple experiments or demonstrations, but for more precise measurements, a professional spectrometer should be used.

4. How do I calibrate my homemade spectrometer?

To calibrate a homemade spectrometer, you will need a known light source with a known wavelength, such as a laser pointer. Place the laser pointer in front of the spectrometer and adjust the position of the screen until you see a clear diffraction pattern. Use the protractor to measure the angle at which the laser's wavelength is diffracted, and use this as a reference point for future measurements.

5. What are some common sources of error when using a homemade spectrometer?

Some common sources of error when using a homemade spectrometer include imperfect diffraction gratings, inconsistent light sources, and human error in measuring and recording the diffraction angles. It is important to be aware of these potential sources of error and try to minimize them as much as possible to obtain more accurate results.

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