A circular loop of wire with a radius of 4.0 cm is in a uniform magnetic field of magnitude 0.060 T. The plane of the loop is perpendicular to the direction of the magnetic field. In a time interval of 0.50 s, the magnetic field changes to the opposite direction with a magnitude of 0.040 T. What is the magnitude of the average emf induced in the loop?
(a) 0.20 V
(b) 0.025 V
(c) 5.0 mV
(d) 1.0 mV
(e) 0.20 mV