일반물리학 2 — Induction and Inductance: Problem 41

41 In Fig. 30-38, a stiff wire bent into a semicircle of radius \( a = 1.4 \text{ cm} \) is rotated at constant angular speed \( 30 \text{ rev/s} \) in a uniform \( 20 \text{ mT} \) magnetic field. What are the (a) frequency and (b) amplitude of the emf induced in the loop?