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# A circular coil of $30$ turns and radius $8.0 \;cm$ carrying a current of $6.0 \;A$ is suspended vertically in a uniform horizontal magnetic field of magnitude $1.0 \;T$.The field lines makes an angle of $60^{\circ}$ with the normal of the coil. Calculate the magnetic of the counter torque that must be applied to prevent the coil from turning .Would your answer change , if the circular coil is replaced by a planar coil of some irregular shape that encloses the same area?

$\begin{array}{1 1} \text{doubles itself} \\ \text{remains the same } \\ \text{reduces by half times the original} \\ \text{ cannot be determined } \end{array}$

$T= nI AB \sin \theta$