Current Loop as a Magnetic Dipole question from MHT CET 2025 (26 Apr, Shift 2)

Answer: (d)

1. $\tau = IAB\sin\theta$; for the same $I$, $B$ and orientation, $\tau \propto A$.
2. For the same perimeter $L$: circle $A = \frac{L^2}{4\pi} \approx 0.080L^2$, square $A = \frac{L^2}{16} \approx 0.063L^2$.
3. The circle has the larger area, so it has the larger torque.
4. So the answer is (d) circular loop is maximum.