physics diffraction

Question

Light with wavelength 666 nm shines on a double-slit. The first-order bright spot is formed at an angle of 0.127 degrees from the central bright spot. Find the spacing between the slits.

Answer 1

Hello Claire

Hope this serves the purpose. The fringe width is given as

w= λ D/ d

θ = w/D

so w= λ /d

or 

d =  λ /θ  Here w = fringe width, D = distance of screen from slits, θ = angular separation in radian , λ = wave length in m

d= separation between two slits

so d = 666* 10 ^-9 / θ    substitute  θ = pi*0.127 / 180 .The answer for d  will be in m