Coherent light of wavelength 540 nm passes through a pair of thin slits that are 3.4 × 10-5 m apart. at what angle away from the centerline does the second bright fringe occur?

Explanation:

The diffraction angles when we have a slit divided into parts are obtained by the following equation:

(1)

Where:

is the width of the slit

is the wavelength of the light  

is an integer different from zero.

Now, the second-order diffraction angle is given when , hence equation (1) becomes:

(2)

Now we have to find the value of :

(3)

Then:

  (4)

  (5)

Finally:

  (6)