$B=\mu_{0} \mu_{r}\left[\frac{N}{2 \pi r}\right] I$ $......(I)$

Substitute $4 \pi \times 10^{-7}$ for $\mu_{o}, 700$ for $\mu_{r}, 250 \times 100$ for $N 0.5$ for $r$ and $1.5$ for $I$ in equation $(I).$

$B=\left(4 \pi \times 10^{-7}\right)(700)\left[\frac{250 \times 100}{2 \pi(0.5)}\right](1.5)$

$=\frac{1400 \times 10^{-7} \times 25 \times 10^{3} \times 1.5}{0.5}$

$=75 \times 1400 \times 10^{-1}$ Tesla

$=10.5$ Tesla