The distance between the ruled lines on a diffraction grating is 1,900 nm.The grating is illuminated at normal incidence with a parallel beam of white light in the 400 nm to 700 nm wavelength band.What is the angular width of the gap between the first order spectrum and the second order spectrum?
A)3.3°
B)4.3°
C)5.3°
D)6.3°
E)2.3°

Question

Quizplus · Accepted Answer

The angular width of the gap between the first and second order spectra can be calculated using the diffraction grating formula: d(sin θ) = mλ. For the first order (m=1) and second order (m=2) spectra, calculate the angles for the maximum and minimum wavelengths (400 nm and 700 nm) and find the difference. The correct calculation gives approximately 3.3°.

The Distance Between the Ruled Lines on a Diffraction Grating