(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A diffraction grating with 620 lines per mm is illuminated with light of wavelength 520 nm. A very wide viewing screen is 2.0 m behind the grating. (Note: 1 mm = 10-3 m; 1 nm =10-9 m)

a) What is the distance between the two m=1 bright fringes? (Express your answer in meters)

b) How many bright fringes can be seen on the screen

2. Relevant equations

m = d(sinθ)/λ

y=Ltanθ

3. The attempt at a solution

A)

d(sinθ)=mλ

=sin_{-1}(1x(520x10_{-9})/(1/620 x10_{-3}))

=18.81

y=Ltanθ

tan(18.81)x2

=.34

.34 x 2 x 2 = 1.36 meters

B) ?

m = d(sinθ)/λ

but when I use this equation I do not get the correct answer. I am at a loss if someone can walk me through this part.

Thanks!

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# Max # of bright fringes

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