Q. Two coils of self inductances $2mH$ and $8mH$ are placed so close together that the effective flux in one coil is completely linked with the other. The mutual inductance between these coil is
A) $4\ mH$
B) $16\ mH$
C) $10\ mH$
D) $6\ mH$
Explanation
(a) Mutual inductance between coils is
$M = K\sqrt{L_{1}L_{2}}$
$\Rightarrow M = 1\sqrt{2 \times 10^{- 3} \times 8 \times 10^{- 3}}\ \ \lbrack\because K = 1\rbrack$
$= 4 \times 10^{- 3} = 4mH$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.