Multiple slits (diffraction gratings)?

Question

what is the wavelength of light that has its second order maximum at 45.0 degrees when falling on a diffraction grating that has 5000 lines per centimeter?

Answer 1

5000 line per cm = 500,000 lines per meter .

dsinΘ = nλ

d = 1/500,000

(1/500,000)sin45 = 2λ

λ = 7.07 x 10^-7 m = 707nm