Rom:Quote:Light of wavelength 630 nm travels through a diffraction grating. A third-order bright fringe is observed at 42.0°. How many lines per cm does the diffraction grating have? Answer with four significant digits.
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Re: Is it Physic or physics
By Rum Troll
Postby Rom » Wed Mar 19, 2014 4:27 pm
Light of wavelength 630 nm travels through a diffraction grating. A third-order bright fringe is observed at 42.0°. How many lines per cm does the diffraction grating have? Answer with four significant digits.
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A slightly convoluted solution going from nanometers to micrometers, but if you are doing physics it should be transparent. What should not be transparent is using 680 nm when 630 nm is the required value. So 3450 lines per cm is correct.
In Rom’s defense it was straight away after his martinis lunch, so he was a little off center. How much off center? about -2.82 degrees. If the angle of incidence to the diffraction grating is -2.82 degrees then 3280 lines per cm for 630 nm lambda is correct.
Another point about this post is Rom’s use of inline images. It’s impressive. It is proof that he has graduated beyond a slide rule.
Suggestion to Rom: try 42 proof instead of 42% martinis.
Is it physic or physics?
By Physic Troll
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