Electromagnetic Induction and Alternating Currents: JEE Main 2026 Physics question

A conducting circular loop is rotated about its diameter at a constant angular speed of $100$ rad/s in a magnetic field of $0.5$ T perpendicular to the axis of rotation. When the loop is rotated by $30^\circ$ from the horizontal position, the induced EMF is $15.4$ mV. The radius of the loop is ________ mm. (Take $\pi=\frac{22}{7}$)