Adouble-slit experiment is set up using red light (l = 701 nm). a first order bright fringe is seen ata given location on a screen. what wavelength of visible light(between 380 nm and 750 nm) would produce a dark fringe at theidentical location on the screen?

b) a new experiment is created with the screen at a distance of 2.1m from the slits (with spacing 0.12 mm). what is the distancebetween the second order bright fringe of light with l = 696 nm and the third order bright fringe oflight with l = 407 nm? (give theabsolute value of the smallest possible distance between these twofringes: the distance between bright fringes on the same side ofthe central bright fringe.)