Q. A solenoid is placed inside another solenoid, the length of both being equal carrying same magnitude of current. The parameters like radius and number of turns are in the ratio 1 : 2 for the two solenoids. The mutual inductance on each other would be
A) $M_{12} = M_{21}$
B) $M_{12} = 2M_{21}$
C) $2M_{12} = M_{21}$
D) $M_{12} = 4M_{21}$
Explanation
(a) $M = K\sqrt{L_{1}L_{2}}$
For perfect coupling $K = 1$
$M_{12} = M_{21}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.