GUJCET 2020 Physics Solved Paper

A coil having 10Am2 magnetic moment is placed in a vertical plane & is free to rotate about its horizontal axis coincides with its diameter. A uniform magnetic field of 2T in the horizontal direction exists such that initially the axis of the coil is in the direction of the field. The coil rotates through an angle of 90º under the influence of magnetic field. The moment of inertia of coil is 0.1‌kg‌m2. What will be its angular speed?