Agrating with 400 lines per mm is illuminated with light of wavelength 600.0 nm. a determine the angles at which maxima are observed b determine the largest order that can be seen with this grating and this wavelength

(a) angles of maxima = 13.9°, 28.7° , 46°, 73.7° on either side

b] largest order = 4

Explanation:

(a) for diffraction maxima,

Here, m is the order, is the wavelength,  is the angle at which maxima occur, d is inter planar spacing.

And we know that lines per mm (N) is related with d as,

Given that the wavelength is,

And

Now,

Therefore,

Here, m can be 1,2,3,4 as sin theta has to be less than 1.

Therefore, angles of maxima = 13.9°, 28.7° , 46°, 73.7° on either side

b] largest order = 4

the answer is f1 and d2 because if you put equal force on those two points the beam would balance trust me on this