Coefficient of coupling between two coils is given as ______, where M = Mutual Inductance, L1 = Self Inductance of coil 1 and L2 = Self Inductance of coil 2
1
\(\rm \frac{M}{\sqrt{L_1L_2}}\)
2
\(\rm \frac{\sqrt{L_1L_2}}{M}\)
3
\(\rm M\sqrt{L_1L_2}\)
4
L1L2.M