Question

Light of 688 nm (6.88 x 10^-7 m) wavelength from a mercury lamp passes through a diffraction grating with a spacing between adjacent slits of 0.003 mm (3 x 10^-6 m). A screen is located a distance of 1.4 m from the grating.
(a) How far from the center of the screen will the first order bright fringe lie?
(b) How far from the center of the screen will the second order bright fringe lie?

Answer 1