Q. What will be the energy loss per hour in the iron core of a transformer if the area of its hysteresis loop is equivalent to 2500 erg/cm³. The frequency of alternating current is 50 Hz. The mass of core is 10 Kg and the density of iron is 7.5 gm/cm³.

(a) 2 × 10^{-2} Joule

(b) 4 × 10^{3} Joule

(c) 6 × 10^{4} Joule

(d) 8 × 10^{5} Joule

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Ans: (c)

Sol: Total energy loss

$ \displaystyle = \nu A V t $

$\displaystyle = \nu A \times \frac{m}{\rho}\times t $

$ \displaystyle = 50 \times \frac{250 \times 10^{-7}}{10^{-6}} \times \frac{10}{7.5 \times 10^3}\times 3600 $