Q 12-06-094JEE MainJEE Main 2022 (26 Jun, Shift 2)Medium
Two coils of self inductance $L_1$ and $L_2$ are connected in series combination having mutual inductance of the coils as $M$. The equivalent self inductance of the combination will be
Answer: (B) $L_1 + L_2 - 2M$
The connecting wire makes the current pass through the two coils in opposite senses, so the flux of each coil through the other opposes its own flux. For series opposing coils
$$L = L_1 + L_2 - 2M$$
Solution by Sreeraj P, M.Sc Physics