Extra Credit: Measure the wavelength of a special light

Measure the wavelength of a particular light source.

This project may be done by teams of 1-2 individuals. The goal is to measure the wavelength of light emitted by a light source I will provide.

Under no circumstances should you aim a laser beam into your eyes, or anyone else's eyes.

There are several ways you might proceed. You may arrange to borrow any materials you need --- little optical bench, some slides with slits, etc. -- by contacting me directly. If you have questions or cannot get the equipment you need, please talk to me.

You might try to use the pattern of light produced by the interference of light passing through a pair of slits. You'll need to project the light onto a screen, measure the distance to the screen, and measure the distance between the central and first (or second, or third, or ...) maxima. You'll need to know the distance between the slits.
You may also try to send a light beam through a single slit and measure the distance between the primary and secondary maxima in the diffraction pattern. Again, you'll need to know the distance between the slit and the screen. You'll need to know the width of the slit.

There may be other methods to measure the wavelength of light, too. Perhaps you may think of some method which involves refraction... You may adopt any method you wish, as long as you describe clearly how your method works.

Once you've made the measurements and calculated the wavelength of light, try to look up the accepted value for the source in question; I can provide some starting points. If there is a large difference (more than 10 percent) between your value and the accepted one, try to explain it.

Submit a report which contains a description of your method, with a clear drawing and all relevant dimensions. Include the data for your experiment, and all calculations. You may also include interesting items you discovered during the course of the procedure.

This page maintained by Michael Richmond. Last modified Apr 29, 1998.