A: Determining the wavelength of the laser in several ways.
One Slit:
Distance between the slit and the wall (L) = 1.055 m
Distance to the first minimum (y) = 0.43 m
M=1
ta n(θ ) = y /L
θ = ta n −1(0.43/1.055)
θ = 0.2335 degrees
Wsin(θ ) = m λ
λ = Wsin(θ )/m
λ = (0.176x10−3)sin(0.2335)/1
λ = 7.17 * 10−7m
Two Slits:
Distance between the slit and the wall (L) = 0.966 m
Distance to the first minimum (y) = 0.027 m
M=5
ta n(θ ) = y /L
θ = ta n −1(0.027/0.966)
θ = 1.60 degrees
Wsin(θ ) = m λ
λ = Wsin(θ )/m
λ = (0.132x10−3)sin(1.6)/5
λ = 7.37 * 10−7m
Single slit diffraction diminishes to zero when the width of the slit is 0 m or when the distance to
the first minimum is 0 m.
Four Slits:
Distance between the slit and the wall (L) = 1.33 m
Distance to the first minimum (y) = 0.0095 m
M=2
ta n(θ ) = y /L
θ = ta n −1(0.0095/1.33)
θ = 0.41 degrees
Wsin(θ ) = m λ
λ = Wsin(θ )/m
λ = (0.176x10−3)sin(0.2335)/2
λ = 4.22 * 10−7m
W = λ /sin(θ )
W = 4.22 * 10−7/sin(0.41)
W = 5.9 * 10−5m
Ten Slits:
Distance between the slit and the wall (L) = 1.29 m
Distance to the first minimum (y) = 0.0295 m
M=5
ta n(θ ) = y /L
θ = ta n −1(0.0295/1.29)
θ = 1.31 degrees
Wsin(θ ) = m λ
λ = Wsin(θ )/m
λ = (0.132x10−3)sin(1.31)/5
λ = 6.04 * 10−7m
W = λ /sin(θ )
W = 6.04 * 10−7/sin(1.31)
W = 2.64 * 10−5m
Yes, there are secondary maxima between the intense spots.
The pattern extends over a longer distance and there are more secondary maxima as the number
of slits increases.
Calculating the spacing between the slits:
Distance between the slit and the wall (L) = 1.35 m
Distance to the first minimum (y) = 0.25175 m
ta n(θ ) = y /L
θ = ta n −1(0.25175/1.35)
θ = 10.56 degrees
Average λ = (7.17 + 7.37 + 4.22 + 6.04) * 10−7/4
Average λ = 6.2 * 10−7m
d = m λ /sin(θ )
d = 6.2 * 10−7/sin(10.56)
d = 3.38 * 10−6 m
B: Polarization Effects
This implies that the laser is unpolarized. The beam was is transmitted when all three polarizers
are oriented the same way, and when the first and third polarizers are oriented the same way, and
the middle polarizer was oriented 45 degrees from the first and third. The diagonal polarizer
allows half of the vertically and horizontally polarized photons through.
The atmosphere partially polarizes the light from the sun due to molecules, and the angle in
which it hits the particles dictates the color of the light observed.