Question

Two coils of self inductances $6mH$ and $8mH$ are connected in series and are adjusted for highest co-efficient of coupling. Equivalent self inductance $L$ for the assembly is approximately

• A. $50mH$
• B. $36mH$
• C. $28mH$
• D. $18mH$

Answer 1

The correct option is C $28mH$

For highest co-efficient of coupling, the equivalent resistance of the assembly is given by:

$L_{eq}=L_1+L_2+2\sqrt{L_1{L}_2}=6+8+2\sqrt{(}6\times 8)=28mH$