English: This I should be able to write this as $\frac{1}{2}{\Phi^{2}\frac{l_{g}}{\mu_{0}A_{g}} = \frac{1}{2}\frac{B_{g}^{2}A_{g}^{2}l_{g}}{\mu_{0}A_{g}} \Rightarrow \frac{B_{g}^{2}}{2\mu_{0}} = W_{f}\ per\ unit\ volume}^{}$ I am writing reluctance as Rel it so that I do not confuse it with the resistance.
Telugu: దీనిని నేను $\frac{1}{2}{\Fi^{2}\frac{l_{g}}{\mu_{0}A_{g}} = \frac{1}{2}\frac{B_{g}^{2}A_{g}^{2}l_{g}}{\mu_{0}A_{g}} {రైట్రో \frac{B_{g}^{2}}{2\mu_{0}} = W_{f}\ per\ unit\ volume}^{{g}$ గా రాస్తున్నాను.