A coil consists of 120 circular loops of wire of radius $4.8 \mathrm{~cm} .$ A current of 0.49 A runs through the coil, which is oriented vertically and is free to rotate about a vertical axis (parallel to the $z$ -axis). It experiences a uniform horizontal magnetic field in the positive $x$ -direction. When the coil is oriented parallel to the $x$ -axis, a force of $1.2 \mathrm{~N}$ applied to the edge of the coil in the positive $y$ -direction can keep it from rotating. Calculate the strength of the magnetic field.