What is the track spacing of a CD?
Cross sectional view of a CD The pits are 125 nm deep, 500 nm wide, and the length can vary anywhere from 850 nm to 3500 nm (3.5 micrometers). The standardized track spacing (called pitch) of 1.6 micrometers is also shown.
What is the typical pit separation width of a CD?
The centres of adjacent grooves are spaced 1.6 micrometres (0.0016 mm) apart. A smaller CD single (80 mm [3.1 inches] in diameter) is also used for audio distribution.
How is a CD an example of diffraction?
As the CD spins, the laser light illuminates various pits and lands simultaneously. When we bounce light off of the CD bottom, the sets of pits and lands will diffract the light and produce a characteristic diffraction pattern on a screen.
What is the distance between two railway tracks?
Standard Gauge The distance between the two tracks in this railway gauge is 1435 mm (4 ft 8½ in). In India, standard gauge is used only for urban rail transit systems like Metro, Monorail and Tram.
What’s the distance between train tracks?
The distance between the inside edges of the rails is defined to be 1435 mm except in the United States and on some heritage British lines, where it is defined in U.S. customary/Imperial units as exactly “four feet eight and one half inches” which is equivalent to 1435.1 mm.
Why would the track pitch of a DVD need to be smaller than the track pitch of a CD?
TRACK PITCH. Pits burned into a recordable CD-ROM, shown in the scanning electron micrograph above, are rougher around the edges than pits in a commercially stamped CD. The smaller pit size on a DVD means the laser beam used in a DVD player must have a shorter wavelength than that in a CD player.
What size is a CD cover?
CD Cover Size Specifications for Printing The finished dimensions for the outside of printed CD covers are 4.724 inches square. Many printed designs include bleed. The “bleed area” is an extra 1/8″ of space for design elements or backgrounds to extend beyond the finished size of your piece.
What are the two types of diffraction?
There are two main classes of diffraction, which are known as Fraunhofer diffraction and Fresnel diffraction.
Why are CDs shiny?
In fact, a CD is almost pure polycarbonate plastic. The surface of a CD is reflective because the disc is coated with a thin layer of aluminum or sometimes gold. The shiny metal layer reflects the laser that is used to read or write to the device. A layer of lacquer is spin-coated onto the CD to protect the metal.
Which country has no railway line?
Bhutan is one of the smallest land-locked nations located in South Asia. Bhutan has no railway network, but there are plans to link the southern parts of Bhutan to the vast Indian railway network.
How to determine the data track spacing on CDs and DVDs?
The experiment will prove tha the data track spacing of a CD is greater than the data track spacing of a DVD. If using a green and red laser pointer to measure the data track spacing on CDs and DVDs, then the data will prove that DVDs have smaller spacing than CDs, because DVDS withhold a greater amount of information than CDs.
How is the diffraction of a laser pointer described?
The diffraction pattern from a bright, monochromatic source (e.g., a laser pointer) interacting with a regular structure can be described by a fairly simple equation: In this equation, d is the spacing of the structure (in this case, the data tracks).
Can you measure things with a laser pointer?
With a laser pointer and a bit of ingenuity, you can make reasonably accurate measurements of things that are too small to measure with more conventional tools. Lego holders for measuring laser diffraction by hair.
How much data can a DVD hold compared to a CD?
DVDs can hold from 7 to 25 times the amount of data on a CD, depending on the DVD format. Do you think the DVD data track spacing will be greater, lesser, or the same as the CD data track spacing? If greater or lesser, how much? Nave, R. (n.d.). Diffraction Grating. HyperPhysics.