Q83 / 90 · JEE Main 2024 (31 Jan Shift 1) · Physics
A small square loop of wire of side is placed inside a large square loop of wire of side . The loops are coplanar and their centers coincide. The value of the mutual inductance of the system is , where ______.
Correct answer: 128
Solution

Flux linkage for inner loop
Therefore, mutual inductance will be
Hence, .
Hence, the correct answer is 128.