CD Diffraction

Introduction
          In this experiment, the distance between the grooves of a compact disc will be determined. One of the method to measure it which we are using in this lab is to use the diffraction of the disc. In this experiment, a laser will be used to shine a CD and the diffraction pattern is then measured and the distance of the grooves will then be able to be calculated.

Experimental


First the lab is set up as follow:

Setup of the lab

Measurement that is made in the experiment

The data from the measurement is tabulated below:

Distance from disc to board (cm)	45.2 ± 0.05
Distance of diffraction pattern (cm)	21.25 ± 1.25
Wavelength of laser (nm)	633 ± 1 nm

The data obtained is as calculated to be d = 1485 ± 20 nm

The theoretical distance of the grooves are 1600 nm

From these data, the percent error is calculated to be 7.19%

Conclusion

              

                Based on the data obtained, the distance between the grooves appear to be 1485 ± 20 nm with a percent error of 7.19%. Some of the error that contributes to the percent error is that there is couple of scratches and smudges. Although the percent error is quite high, it is still accurate as the true value is still within uncertainty.