Q. The mass of specimen of a ferromagnetic material is 0.6 kg and the density is $7.8 \times 10^{3}kg\ m^{- 3}$. If the area of hysteresis loop of alternating magnetizing field of frequency 50 Hz is 0.722 MKS units, then hysteresis loss per second will be
A) $27.77 \times 10^{- 5}\ J$
B) 2.777 $\times 10^{- 5}\ J$
C) 27.27 $\times 10^{- 4\ }J$
D) 27.77 $\times 10^{- 6\ }J$
Explanation
(c) If $V =$volume of the material = mass/density
$A =$ area of hysteresis loop
$v =$ frequency of alternate magnetic field applied
$t =$ time for which field is applied
Then, energy loss in the material in $t$ second is
$E = VA\ vt = \left( \frac{m}{d} \right)A\ vt$
$= \frac{0.6}{7.8 \times 10^{3}} \times 0.722 \times 50 \times 1$
$= 2.77 \times 10^{3}$
$= 27.7 \times 10^{- 4}$ J
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.