Young's double slit experiment is one of the quintessential experiments in physics. The availability of low cost lasers in recent years allows us to perform the double slit experiment rather easily in class. Your professor shines a green laser (560 nm) on a double slit with a separation of 0.108 mm. The diffraction pattern shines on the classroom wall 3.0 m away. Calculate the fringe separation between the third order and central fringe.

 y = 4.666 10⁻² m

Explanation:

The constructive interference experiment for the double slit

         d sin sin θ = m λ

Let's use trigonometry to find a sine relationship.

         Tan θ = y / L

          tan θ = sin θ/ cos θ

in these experiments the angles are very small

           tan θ = sin θ

           sin θ = y / L

            = m λ

              y =

we replace the values

              y = 3  560 10⁻⁹ 3.0 / 0.108 10⁻³

              y = 4.666 10⁻² m

which statement about this sum is true? −245+2.7