The coefficient of mutual inductance of two coils is $6\, mH$. If the current flowing in one is $2\, A$,then the induced $e.m.f.$ in the second coil will be:

Two concentric circular coils having radii $r_1$ and $r_2$ $(r_2 \ll r_1)$ are placed co-axially with centres coinciding. The mutual induction of the arrangement is (Both coils have single turn,$\mu_0 =$ permeability of free space).

$A$ coil of radius '$r$' is placed on another coil (whose radius is '$R$' and current flowing through it is changing) so that their centres coincide $(R \gg r)$. If both the coils are coplanar,then the mutual inductance between them is $(\mu_0 = \text{permeability of free space})$

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

$A$ varying current at the rate of $3 \, A/s$ in a coil generates an $e.m.f.$ of $8 \, mV$ in a nearby coil. The mutual inductance of the two coils is:

Write the formula for the mutual inductance of two very long coaxial solenoids of length $l$.