The figure shows three loops, U, V and W, made from equal lengths of the same wire: a circle, a square and an equilateral triangle. Each carries the same current. Each is placed in turn in the same uniform magnetic field, with its plane parallel to the field. Compare the torques $\tau_U$, $\tau_V$ and $\tau_W$ on the loops. Which option is correct?

Fig. 1: Three closed loops of the same wire, each with the same current as shown by arrows, in the plane of the page and labelled U, V and W: a circle, a square and an equilateral triangle. Horizontal arrows across the page show a uniform magnetic field B lying in the plane of the page, parallel to the top edge of the square. The wire in each loop has the same length.