Two circuits have a mutual inductance of $0.1\, H$. What average $e.m.f.$ is induced in one circuit when the current in the other circuit changes from $0$ to $20\, A$ in $0.02\, s$ (in $, V$)?

$A$ pair of adjacent coils has a mutual inductance of $1.5 \ H$. If the current in one coil changes from $0 \ A$ to $10 \ A$ in $0.5 \ s$,what is the change of flux linkage with the other coil (in $Wb$)?

$A$ solenoid of length $60 \ cm$ with $15$ turns per $cm$ and area of cross-section $4 \times 10^{-3} \ m^2$ completely surrounds another co-axial solenoid of the same length and area of cross-section $2 \times 10^{-3} \ m^2$ with $40$ turns per $cm$. The mutual inductance of the system is: (in $mH$)

Find the mutual inductance between two coaxial circular loops of radius $a$ separated by a distance $l$,where $l >> a$.

$A$ pair of adjacent coils have a mutual inductance, $M$. The current in one coil changes from $0 \,A$ to $16 \,A$ in $0.3 \,s$, and the change of flux linkage with the other coil is $40 \,Wb$. The value of $M$ is: (in $\,H$)

The mutual inductance between two coils is $1.25 \ H$. If the current in the primary coil changes at the rate of $80 \ A/s$, then the induced $e.m.f.$ in the secondary coil is ...... $V$.