If the grating constant is 400 lines/mm, what is the spacing between the lines? a. 1/400 b. 1/40 cm c. 1/400 mm d. 400 mm e. 40 cm

c. 1/400 mm

Explanation:

The spacing between line is simply the inverse of the grating constant. Being the grating constant. The grating constant is just the number of lines per unit of length, and in this case its value is 400 lines/mm, therefore, the spacing d will be 1/400 mm.