Author Topic: Physics diffraction gratings  (Read 807 times)

Offline tmisterr

  • SF Citizen
  • ***
  • Posts: 186
  • Reputation: 43273
Physics diffraction gratings
« on: February 27, 2010, 10:03:54 am »
If you a question like the 3rd order of light incident normal to a diffration grating happens a theta=45 degreed, find the highest number order possible, how do u approach it?

Offline astarmathsandphysics

  • SF Overlord
  • *********
  • Posts: 11271
  • Reputation: 65534
  • Gender: Male
  • Free the exam papers!
Re: Physics diffraction gratings
« Reply #1 on: February 27, 2010, 10:25:12 am »
sin theta =nw/d where w=wavelength
sin 45= 3w/d
1/3sqrt(2)=w/d
1>nw/d=n*1/3sqrt(2)
n<3sqrt(2)=4.2....
highest order =4

Offline tmisterr

  • SF Citizen
  • ***
  • Posts: 186
  • Reputation: 43273
Re: Physics diffraction gratings
« Reply #2 on: February 28, 2010, 03:22:23 pm »
thanks alt :)