The surface of a CD contains microscopic pits arranged in a spiral track. A laser beam is directed onto the disc, and the reflected light intensity changes as the beam passes over pits and lands (areas between pits). A photodetector reads these changes in reflected light, which are then converted into the digital signal representing the audio.
For reproducing sound, a CD (Compact Disc) audio player uses a
Asked in UPPCS Prelims 2000 · Topic: Optics (Laser: Principles and applications)
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