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?

Respuesta :

Answer: [tex]1.8\°[/tex]

Explanation:

The diffraction angles [tex]\theta_{n}[/tex] when we have a slit divided into [tex]n[/tex] parts are obtained by the following equation:

[tex]dsin\theta_{n}=n\lambda[/tex] (1)

Where:

[tex]d=3.4(10)^{-5}m[/tex] is the width of the slit

[tex]\lambda=540 nm=540(10)^{-9}m[/tex] is the wavelength of the light  

[tex]n[/tex] is an integer different from zero.

Now, the second-order diffraction angle is given when [tex]n=2[/tex], hence equation (1) becomes:

[tex]dsin\theta_{2}=2\lambda[/tex] (2)

Now we have to find the value of [tex]\theta_{2}[/tex]:

[tex]sin\theta_{2}=\frac{2\lambda}{d}[/tex] (3)

Then:

[tex]\theta_{2}=arcsin(\frac{2\lambda}{d})[/tex]   (4)

[tex]\theta_{2}=arcsin(\frac{2(540(10)^{-9}m)}{3.4(10)^{-5}m})[/tex]   (5)

Finally:

[tex]\theta_{2}=1.8\°[/tex]   (6)