Physics 1I Lab Ouiz 10 Pg. 2 of 2 6. By definition, a diffraction grating is com
ID: 2304516 • Letter: P
Question
Physics 1I Lab Ouiz 10 Pg. 2 of 2 6. By definition, a diffraction grating is composed of a planar non-transparent substrate containing a parallel series of linear grooves (a.k.a. "lines" or "rulings"), which are transparent. If a diffraction grating has 500 "lines" per millimeter, (a) what is d, the spacing between two adjacent "lines"? (b) Do you know the width of each "line"? 7. How is the spacing between two adjacent "lines"d compared to the wavelength 2.? Can one be much larger or smaller than the other for you to observe diffraction patterns? 8. In the diagram on Lab Manual page 33, if y 20 cm and L 40 cm, what is the value of 0? 9. Also in the same diagram, if d 1 mm/500 lines what is the approximate value of r2-r?Explanation / Answer
A diffraction grating with 500 grooves per mm means in one mm length of the grating there are 500 transparent rulings and 500 adjacent opaque spacings. Considering Both transparent and opaque spacing being of equal thickness we can answer the questions. For part 8 and 9 the diagram is needed.
6.(a) d = 1/500 in mm = 0.002 mm = 2 micro meter.
6.(b) width of each line is equal to half of d = 1 micro meter.
7. d should be comparable to the wavelength of light to be diffracted ; not much larger or smaller.
Thank you