The torque experienced by a given current carrying loop in a uniform magnetic field $\overrightarrow{B}$ given by $B_0(\overrightarrow{i}-\overrightarrow{j})$ would have magnitude

A non-conducting non-magnetic rod having circular cross section of radius R is suspended from a rigid support as shown in the figure. A light and small coil of 300 turns is wrapped tightly at the left end of the rod where uniform magnetic field B exists in vertically downward direction.Air of density $\rho$ hits the half of the right part of the rod with velocity V as shown in the figure. What should be current in clockwise direction (as seen from O) in the coil so that rod remains horizontal? Give answer in m A. Given

$\frac{2}{Lv}\sqrt{\frac{\pi RB}{\rho }}=\frac{1}{\sqrt{5}}{ \mathrm{A}}^{-1/2}$