Two loops with sides L and l (L>>l) are placed concentrically and coplanar as shown in fig. (9). The
mutual inductance of the system is proportional to
l2/L2
L2/l2
l/L2
l2/L
The value of B is given byB=22μ0iπLThe flux linked with the smaller loopΦ=Mi=BA=Bl2∴Mi=22μ0il2−I or m∝l2/L