pit

Examples of pit in the following topics:

• Using Interference to Read CDs and DVDs

  • These discs are flat, usually made of aluminum, and have microscopic pits and lands on one of the flat surfaces (as shown in ).
  • If the beam hits a pit, it gets scattered and is recorded as a value of zero.
  • These microscopic pits and lands cover the entire surface of the disc in a spiral path, starting in the center and working its way outward.
  • These pits also act as slits and cause the light to be diffracted as it is reflected back, which causes an iridescent effect.
  • In this early version of an optical disc, you can see the pits and lands which either reflect back light or scatter it.

• Diffraction Gratings: X-Ray, Grating, Reflection

  • This is a side effect of their manufacture, as one surface of a CD has many small pits in the plastic, arranged in a spiral; that surface has a thin layer of metal applied to make the pits more visible.
  • The structure of a DVD is optically similar, although it may have more than one pitted surface, and all pitted surfaces are inside the disc.

• Angular Position, Theta

  • Each pit used to record sound along this line moves through the same angle in the same amount of time.
  • The pits along a line from the center to the edge all move through the same angle Δ in a time Δt.

• Angular Velocity, Omega

  • To find the precise relationship between angular and linear velocity, we again consider a pit on the rotating CD.
  • This pit moves an arc length Δs in a time Δt, and so it has a linear velocity v = Δs/Δt.

• X-Ray Diffraction

  • The rainbow pattern that appears is a result of the light being interfered by the pits and lands on the disc that hold the data. shows this effect.

• Humans: Work, Energy, and Power

  • Shivering, in fact, is an involuntary response to low body temperature that pits muscles against one another to produce thermal energy in the body (and do no work).