Question

In a cassette player, material used for coating magnetic tapes is:
A. Cobalt
B. $CoF{{e}_{2}}{{O}_{4}}$
C. $NiF{{e}_{2}}{{O}_{4}}$
D. Nickel

Answer 1

A ferromagnetic material is used for coating the magnetic tape of a cassette player. Ferromagnetic materials are the materials which have a very large, positive susceptibility to an external magnetic field. They exhibit strong attraction towards the magnetic field and can retain the magnetic properties even after being removed from the external magnetic field.

Complete answer:
As discussed in the hint, a ferromagnetic material is used for coating the magnetic tape of a cassette player. Ferrites are used for this purpose such as $MnF{{e}_{2}}{{O}_{4}}, FeF{{e}_{2}}{{O}_{4}}, NiF{{e}_{2}}{{O}_{4}}$ etc.
So, we can say that $NiF{{e}_{2}}{{O}_{4}}$ is used for coating the magnetic tapes of a cassette player.

So, the correct answer is “Option C”.

Additional Information:
$NiFe{{O}_{4}}$ is read as Nickel Ferrite. Thanks to its usual ferrimagnetic characteristics, lower eddy current losses, moderate conductivity and elevated electrochemical stability, nickel ferrite is one of the multifaceted and technologically relevant soft ferrite products. It has a counter spin structure.

Note:
Three-dimensional $NiFe{{O}_{4}}$ nanofibers with tunable morphology were successfully prepared by the electrospinning process and subsequent annealing. Multiparticle-chain NiFe2O4 nanofibers with differing crystallite sizes from 5.3 nm to 30.2 nm and single-particle-chain with crystallite size of 64.5 nm were achieved at 500–800 and $900{}^\circ$ C, respectively.