Measuring Wavelength?

[Warske]

...how far would the wall have to be away from the source to resolve 1nm using a steel ruler with 1/4" divisions? ...

You mean you want me to actually work for my +1?

If the wall is 41 feet away, and you use a 500 line/mm grating, a red 660 nm laser will shift about 1/4" along the wall when the wavelength changes by 1 nm. The beam from a green laser would shift about the same amount but just a bit less because the wall is not curved.

That's somewhat far for practical purposes, so you could use a ruler with finer divisions or a grating with more lines/mm. 500/mm is rather low actually, but it is what Teachersource is selling.

 

[Diode_Virgin]

thanks! I would have thought it would be farther.