Single Slit and Double Slit Diffraction

4. Record the displacement measured by the rotary motion sensor and the intensity of light measured by the light sensor.

Data

Laser wavelength - 6.7x10-7 meters

Distance from the slit to the light sensor - 0.72 meters

Single slit diffraction pattern with a 2x10-5 m wide slit

Single slit diffraction pattern with a 4x10-5 m wide slit

Single slit diffraction pattern with a 8x10-5 m wide slit

Double slit diffraction pattern with a 4x10-5 m wide slit and 2.5x10-4 m between slits

Double slit diffraction pattern with a 4x10-5 m wide slit and 5.0x10-4 m between slits

Double slit diffraction pattern with a 8x10-5 m wide slit and 2.5x10-4 m between slits

Data Analysis

By observing the characteristics of the diffraction patterns produced, one can see the difference between the single slit diffraction patterns and double slit diffraction patterns. The single slit diffraction patterns have a central peak with peaks of reducing magnitude surrounding the central peak as they get further away from central peak.The double slit diffraction patterns have a series of peaks which mimic the rough shape of that found in single slit diffraction patters. The double slit diffraction patterns are more complex than those of produced by single slit diffraction patterns.

Evaluation

Although the general shapes of the expected diffraction pattern can be seen in all cases, there are many instances of minor aberrations in the graphs. These can be attributed to many factors; exposure to external light, misaligned equipment or human errors when manually sliding the light sensor.

Conclusion

All in all, the graphs seem consistent with the patterns predicted by theory. The expected diffraction pattern is clearly seen in all cases. Thus, the diffraction pattern predicted by theory was confirmed by this lab.

Physics IBH-2 Mr. Butler

Joseph Florendo November 22, 2001