Q. The mass of a specimen of a ferromagnetic material is 0.6kg and its density is 7.8 × 10³ kg/m³. If the area of hysteresis loop of alternating magnetising field of frequency 50Hz is 0.722 MKS units then the hysteresis loss per second will be
(a) 277.7 × 10-5 Joule
(b) 277.7 × 10-6 Joule
(c) 277.7 × 10-4 Joule
(d) 277.7 × 10-3 Joule
Ans: (a)
Energy Loss per sec
$ \displaystyle = \nu A V t $
$ \displaystyle = \nu \times A \times \frac{m}{\rho} t $
$ \displaystyle = 50 \times 0.722 \times \frac{0.6}{7.8 \times 10^3} \times 1 $
= 277.7 × 10-5 Joule