In a Young's double-slit experiment, a set of parallel slits with a separation of 0.132 mm is illuminated by light having a wavelength of 554 nm and the interference pattern observed on a screen 4.50 m from the slits

Complete Question

In a Young's double-slit experiment, a set of parallel slits with a separation of 0.132 mm is illuminated by light having a wavelength of 554 nm and the interference pattern observed on a screen 4.50 m from the slits

(a) What is the difference in path lengths

from the two slits to the location of a third order bright fringe on the screen?

________ µm

(b) What is the difference in path lengths from the two slits to the location of the third dark fringe on the screen, away from the center of the pattern?

________ µm

a

b

Explanation:

Generally the path difference for a bright fringe  is mathematically represented as  

Where is n the order of fringe with values n = 0,1,23,4,...

                is the wavelength

For n = 2 i.e for the third  fringe

       The path difference becomes

substituting values

For dark fringe the formula is

 Where n = 2 for third fringe