A square loop of side 2a and carrying current I is kept in xz plane with its centre at origin. A long wire carrying the same current I is placed parallel to z-axis and passing through point (0, b, 0), (b >> a). The magnitude of torque on the loop about z-axis will be
![](https://sahay.guru/wp-content/uploads/2021/09/Solution-15A-6-469x1024.jpg)