Current Loop as a Magnetic Dipole question from JEE Main 2022 (26 Jul, Shift 2)

Answer: (b)

1. From the figure, the inner loop current is anticlockwise ($\vec{M}_1$ along $+\hat{k}$) and the outer loop current is clockwise ($\vec{M}_2$ along $-\hat{k}$).
2. $M_1 = I\pi r_1^2 = 7\pi(0.3)^2$, $M_2 = I\pi r_2^2 = 7\pi(0.5)^2$
3. $\vec{M} = 7\pi(0.09 - 0.25)\hat{k} = -1.12\pi\hat{k} \approx -3.5\hat{k}$ A m$^2$
4. So the answer is (b) $-\frac{7}{2}\hat{k}$ A m$^2$.