A circular coil has moment of inertia 0.8 kg m²
around any diameter and is carrying current to
produce a magnetic moment of 20 Am²
. The coil is kept initially in a vertical position and it can
rotate freely around a horizontal diameter. When a uniform magnetic field of 4 T is applied along the
vertical,it starts rotating around its horizontal diameter. The angular speed the coil acquires after
rotating by 60^o will be: