Two coils of self-inductance $2 \, mH$ and $8 \, mH$ are placed so close together that the effective flux in one coil is completely linked with the other. The mutual inductance between these coils is......$ mH$

$X$ and $Y$ are two metallic coils arranged in such a way that when the steady change in current flowing in coil $X$ is $4 \ A$,the change in magnetic flux associated with coil $Y$ is $0.4 \ Wb$. The mutual inductance of the system of these coils is . . . . . . $H$.

Two coils have a mutual inductance of $0.005\,H$. The current in the first coil changes according to the equation $I = I_0 \sin \omega t$,where $I_0 = 10\,A$ and $\omega = 100\pi \,rad/s$. The maximum value of $emf$ in the second coil will be: (in $\pi \,V$)

An alternating current of angular frequency $\omega = 200 \, rad/sec$ and peak value $I_0 = 1 \, A$,as shown in the figure,is applied to the primary coil of a transformer. If the coefficient of mutual induction between the primary and the secondary coil is $M = 1.5 \, H$,the magnitude of the induced voltage in the secondary coil will be.....$V$.

Consider $I_1$ and $I_2$ are the currents flowing simultaneously in two nearby coils $1$ and $2$,respectively. If $L_1$ is the self-inductance of coil $1$ and $M_{12}$ is the mutual inductance of coil $1$ with respect to coil $2$,then the value of the induced emf in coil $1$ will be:

$A$ very long straight conductor and an isosceles triangular conductor lie in a plane and are separated from each other as shown in the figure. If $a = 10 \ cm$,$b = 20 \ cm$,and $h = 10 \ cm$,find the coefficient of mutual induction.