A parallel beam of light of wavelength 450 nm falls normally on a diffraction grating which has 300 lines/mm. What is the total number of transmitted maxima?

Question

anonymous · Answer

1D Areesha i try to solve it.

anonymous · Answer

What would d be?

vincent-lyon.fr · Answer

Answer should be 15 maxima for orders$$0; \pm1;\pm2;\pm3;\pm4;\pm5;\pm6;\pm7$$

anonymous · Answer

Yes, but how did you get that answer? I can't seem to recall the formulae or how to apply them...

vincent-lyon.fr · Answer

Scroll down to the fundamental formula beginning with θm = ... Assume θi = 0 (incident ray falls normally on grating) Solve for all possible values of θm. You will find m can be from -7 to +7 Page is: http://en.wikipedia.org/wiki/Diffraction_grating

anonymous · Answer

As
n *lamda=d sin theta
theta=90
so 
n=d/ lamda..........(1)
d=10^-3m/300=3333.0*10^-9 m 
put the value of d and lamda in (1) , we get 
n=7

anonymous · Answer

okay your wel come

anonymous · Answer

Yeah, that confused me a bit but it's all good now, thanks!