IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => Subject Doubts => GCE AS & A2 Level => Sciences => Topic started by: tmisterr on February 27, 2010, 10:03:54 am

Title: Physics diffraction gratings
Post by: tmisterr 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?

Title: Re: Physics diffraction gratings
Post by: astarmathsandphysics 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

Title: Re: Physics diffraction gratings
Post by: tmisterr on February 28, 2010, 03:22:23 pm

thanks alt :)