A system displaying a hysterisis loop such as a ferromagnet, is a device for storing memory?' Explain the meaning of this statement.

What king of ferromagnetic material is used for coating magnetic tapes in a cassette player, or for building 'memory stores' in a modern computer ?

Explain the meaning of the statement 'electric charge of a body is quantized'.

Consider the following statements A and B and identify the correct choice in the given answers . (A) Suceptibility of paramagnetic material does not depend upon temperature (B) Ferromagnetism is explained by domain theory