A laser beam was positioned so that the beam would pass through a small hole on a surface. Then, the beam would hit the readable surface of a CD, and two dots would appear on the surface.
The distance between the red dots is defined as the first order maxima. The light emitted by the laser box has a wavelength of λ = 633 nm. The distance between grooves,a, in a CD is related in the following formula:
sin θ = λ/a = L/(x^2 +L^2)^1/2
Solving for a yields;
a = [λ*(x^2 +L^2)^1/2]/L
Data:
2x = 0.024 +/- 0.001m; x = 0.0120 +/- 0.00050 m
L = 0.048 +/- 0.0005 m
λ = 6.33*10^-7 m
a = [6.33*10^-7*( 0.0120 +/- 0.00050^2 + 0.048 +/- 0.0005^2)^1/2]/ 0.048 +/- 0.0005
a = 6.52*10^-7 +/- 8.2*10^-9 m
a = 652nm
When compared to the manufacturers standard value of 1600 nm, we could see an enormous inconsistency with a percent error of 84%.
Such a large percent error suggests that there must have been systematical errors while carrying out the experiment like improper measuring techniques or incorrect positioning of the laser.
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