Adouble-slit experiment is set up using red light (λ = 706 nm). a first order bright fringe is seen at a given location on a screen. what wavelength of visible light (between 380 nm and 750 nm) would produce a dark fringe at the identical location on the screen? λ =

λ = 470.66 nm

Explanation:

for bright fringe

D= distance between slit and screen

d= distance between the slits

for first order bright fringe m = 1,

for dark fringe,we have

Now to get the dark fringes at the same location we should have;

(706)D/d = (m + 1/2)λD/d    

put m = 1

(1 + 1/2)λ = (706)

λ = 470.66 nm