Physics problem related to "Nature of light".

Problem:
Light of wave length 5500A° is diffracted by a gratting having 1900 lines per cm. Compute the angular deviation of the third order image.
Data:
Change "λ=5500A" to (5500 X 10^-10), (1A°=10^-10)
Take "Order of image" as "m=3".
No. of lines per cm= 1900 (change it in metre), Use Formula d= 1m/No. of lines
Angular deviation= theta = θ = ?, Use Formula mλ= d Sinθ

If you can improve data so improve it and then solve the problem, its answer is θ=0.057°.
If answer is correct then prove it and if not then correct it.

Thanks