A transformer is working on 220V.50 Hz a.c. supply. The iron core of the transformer has a mass of 8.4 kg.. From the plot of B-H loop for the core, it is found that area of hte loop is `480 J m^-3` . If the density of iron is 7,500 `kgm^-3`, find the loss of energy in the core of transformer in 1 hour.

The area of B - H loop for a ferromagnetic material is 540 J m^-3 . If the absolute permeability of free space is 4pi xx 10^-7 J A^-2 m^-1 , find the area of the I - H loop of the ferrogmangnetic material.

An iron smaple having mass 8.4 kg is repeatedly taken over cycles of magnetisation and demagnetisation at a frequency of 50Hz. It is found that energy of 3.2 J is dissipated as heat in the sample in 30 minutes. If the denstiy of iron is 7200 kg m^-3 , calculate the value of energy dissipated per unit volume per cycle in the iron sample.

They hysteresis loss for a speciment of iron weighing 12 kg is equivalent to 300 J m^-3 cyc^-1 . Find the loss of energy per hour at 50 cycles s^-1 . Given, density of iron = 7,500 kg m^-3