Cheap Audio Tape
This audio tape is about the cheapest that can be bought on the High Street.
Audio tapes consist of a thin base tape (usually polymeric) onto which Ferric Oxide (Fe2O3 Powder is deposited.
The oxide is mixed with binder to aid adhesion to the tape and a dry lubricant powder to reduce wear from friction between the tape and the tape-recorder head.
The ferric oxide is ferromagnetic, and can be permanently magnetised by a magnetic field. Each particle of ferric oxide forms a magnetic dipole, which can be read by the recording head.
A typical audio tape records 60 to 90 minutes of music or data, although data recording is not commonly done using tapes. The data is analogue, not digital, and the highest frequency recorded depends on the size of the ferric oxide particles.
You should compare the size of the ferric oxide particles on this cheap tape with the particles on an expensive tape. Do you think it is worth spending the extra money?