a. Find the current $I$ required to establish a flux $\boldsymbol{\phi}=2.4 \times 10^{-4} \mathrm{~Wb}$ in the magnetic circuit of Eigure P14.14. Here area(throughout) $=2 \times 10^{-4} \mathrm{~m}^2$, $l_{a b}=l_{e f}=0.05 \mathrm{~m}, l_{a f}=l_{b e}=0.02 \mathrm{~m}, l_{b c}=l_{d c}$, and the material is sheet steel.
b. Compare the mmf drop across the air gap to that across the rest of the magnetic circuit. Discuss your results, using the value of $\mu$ for each material.