BASICS OF A CD

           

 'CD' stands for Compact Disk.A CD is a round-shaped optical device,that is read by a laser beam.A standard Cd has a diameter of 120mm(4.63in) and thickness of about 1.2mm.CD has a weight of approximately 5 grams.The CD consists of an inner spindle hole at the center,for clamping purposes,of about 15mm in diameter.The upper side of the CD constitutes a label layer while the lower side consists of a transparent polycarbonate layer.

Compact Disk was originally intended for audio music storage but later evolved for purposes such as data and video storage.A normal CD will have a capacity of about 700mb of data or 80min of audio/video.