The Spacing of Ruled Lines on a Diffraction Grating Is

Multiple Choice

The spacing of ruled lines on a diffraction grating is 1770 nm.The grating is illuminated at normal incidence with a parallel beam of white light in the 400 nm to 700 nm wavelength band.The longest wavelength that appears in the third order spectrum is closest to:

A) 590 nm
B) 570 nm
C) 550 nm
D) 530 nm
E) 610 nm