Final answer:
The minutes rating on a CD indicates the total amount of music that can be stored, with an 80-minute CD capable of holding that length of audio. This is read by a CD player through pits and bumps on the CD's surface, encoded as binary data.
Step-by-step explanation:
The minutes rating on a CD refers to the total amount of audio that can be stored on the disc when it's used for music. For a CD with a 700 MB capacity and an 80-minute rating, this means that it can store up to 80 minutes of music at the standard encoding rate. This rate is set for the typical CD player which reads the digital information encoded as pits and bumps on the surface of the CD. These pits and bumps form a spiral track that begins at the center of the disc and contains the binary data that is converted back into audio by the CD player's laser and electronics.
Music CDs were once the predominant format for listening to music, before being replaced by streaming services. They use a laser to create the pits on their surface, which are then read by the CD player's laser and this technology allowed them to have a much larger information-storage capacity than their predecessors, such as vinyl records and cassette tapes. A CD's storage capacity is enabled by the precision with which these pits are created and read, allowing large amounts of digital information to be stored on a relatively small physical medium.