Why is there a spectrum on the back of a CD or DVD?

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SUMMARY

The spectrum observed on the back of a CD or DVD is a result of diffraction, where the tracks and sectors on the disc act as a diffraction grating. This phenomenon occurs when light bends around the edges of these microscopic structures, leading to the overlapping of various colors in a continuous spectrum. The discussion confirms that the correct explanation for this visual effect is indeed diffraction, rather than dispersion.

PREREQUISITES
  • Understanding of light behavior, specifically diffraction and dispersion.
  • Familiarity with optical phenomena and their applications.
  • Basic knowledge of the structure of CDs and DVDs.
  • Awareness of grating elements and their role in optics.
NEXT STEPS
  • Research the principles of diffraction grating in optics.
  • Explore the differences between diffraction and dispersion in light behavior.
  • Study the physical structure of CDs and DVDs and how they interact with light.
  • Investigate practical applications of diffraction in technology and science.
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Students of physics, optical engineers, and anyone interested in the principles of light behavior and its applications in everyday technology.

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Homework Statement




When i see the back of a CD or DVD, there is a spectrum, in which the various colours are overlapping with each other(continuous spectrum)

Homework Equations




What is the reason for this phenomenon, diffraction or dispersion?

The Attempt at a Solution


Diffraction means bending of light around the edges of obstacles and Dispersion is splitting of white light into its constituent colours or wavelength.
I presume the tracks and sectors present in CD or DVD acts as slits and rulings akin to grating element. Am i correct? Pls help revered members.
 
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Thanks a lot ehild
 

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