Q.

A small square loop of wire of side L is placed inside a large square loop of wire of side L(L=l2). The loops are coplanar and their centers coincide. The value of the mutual inductance of the system is x×10-7H, where x= ____.                  [2024]


Ans.

(128)

Flux linkage for inner loop.

ϕ=Bcenter·l2=4×μ0i4πL2(sin45+sin45)l2

ϕ=22μ0iπLl2

M=ϕi=22μ0l2πL=22μ0π

=224ππ×10-7=128×10-7 H

x=128