Coil 1 has $L_{1}=25 \mathrm{mH}$ and $N_{1}=100$ turns. Coil 2 has $L_{2}=$
40 $\mathrm{mH}$ and $N_{2}=200$ turns. The coils are fixed in place; their mutual inductance $M$ is 3.0 $\mathrm{mH}$ . $\mathrm{A} 6.0 \mathrm{mA}$ current in coil 1 is changing
at the rate of 4.0 $\mathrm{A} / \mathrm{s}$ (a) What magnetic flux $\Phi_{12}$ links coil $1,$ and
(b) what self-induced emf appears in that coil? (c) What magnetic
flux $\Phi_{21}$ links coil $2,$ and $(\mathrm{d})$ what mutually induced emf appears in
that coil?