\(r_2=1000\,cm , N_2=200\)
\(\phi_{1.2}=M I_2\)
\(N_2 \vec{B}_2 \cdot N_1 \vec{A}_1=M I_2\)
\(\Rightarrow N_1 N_2 \frac{\mu_0 I_2}{2 r_2} \cdot \pi r_1^2=M I_2\)
\(\Rightarrow M=\frac{10 \times 200 \times 4 \pi \times 10^{-7} \times \pi \times(0.01)^2}{2 \times 10}\)
\(\Rightarrow M=4 \times 10^{-8}\)