The Spacing of Ruled Lines on a Diffraction Grating Is

Multiple Choice

The spacing of ruled lines on a diffraction grating is 1900 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 angular width of the gap between the first order spectrum and the second order spectrum is closest to:

A) 3.3°
B) 4.3°
C) 5.3°
D) 6.3°
E) 2.3°