Light from a laser (lambda= 406.192 nm) is used to illuminate two narrow slits. The interference pattern is observed on a screen 5.937 m behind the slits. 24 bright fringes are seen, spanning a distance of 39.835 mm (they are not necessarily centered, you don't know where the center is, this is not important here). What is the spacing (in mm) between the slits? Give the numerical answer only, in m

The spacing between the slits is                    

Explanation:

From the question we are told that

  The wavelength of the light is

   The distance of the slit from the screen is

    The number of bright fringe is

     The  length the fringes span is  

The fringe width (i.e the distance of between two successive bright or dark fringe) is mathematically represented as

Where d is  the distance between the  slits

            is the fringe width which can also be evaluated as

Substituting values

Making d the subject of formula in the above equation

Substituting values