When a coherent light source such as a laser light passes through two parallel s

Question

When a coherent light source such as a laser light passes through two parallel slits, an interference pattern is observed on the screen. (This is the Young's double slit experiment which proves that light exhibits wave behavior.) For the interference pattern to be observed, the width of the slits and the distance between the two slits must both be in the order of a millimeter. The Figure below shows the setup and the interference fringes. The Figure is not to scale, L is typical of the order of a couple of meters whereas y is of the order of cm.

Figure 3 - Interference fringes from two narrow and parallel slits.

The next two parts will make use of Figure 3.

What is the distance from the central maximum to the 7th minimum? (This is y in Figure 2.)
answer: 1.16 cm

I need help doing just the second part, which is finding the wavelength.

Explanation / Answer

d sin() =(n+1/2)*

rearranging for we get
= d sin() / (n+1/2)

now using euclidian geometry we conclude from the figure that
tan = y / L (tangent = oppositve / adjacent)
L is given at 115cm, you solved for y as 1.16
so the inversese tangent of y/L is the angle
so would equal 89 degrees, this seems unlikely, and I am going to from here out assume that L was supposed to be 1.15 cm and not m, which makes the 44.75 if this is a false assumtion just switch those two angles in the following

= .047cm *sin(44.75) / (7.5)
or = .004412 cm
note that wavelengths are usually given in nm which would be 44,119 nm

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.