The mutual inductance of two coils is 45 mH . The self-inductance of the coils are $\mathrm{L}_1=75…
The mutual inductance of two coils is 45 mH . The self-inductance of the coils are $\mathrm{L}_1=75 \mathrm{mH}$ and $L_2=48 \mathrm{mH}$. The coefficient of coupling between the two coils is
0.3
0.4
0.75
1.0
Solution
Mutual inductance due to two coils,
$\begin{aligned}
& M=K \sqrt{L_1 L_2} \\
\therefore \quad K & =\frac{M}{\sqrt{L_1 L_2}}=\frac{45}{\sqrt{75 \times 48}}=\frac{45}{60}=0.75
\end{aligned}$