what is the average induced emf?

2 wires form a loop with a diameter of 28.6 cm. If the loop rotates parallel to a 2.7 T magnetic field in 0.49 s, what is the average induced emf?

0.484 V
0.661 V
0.708 V
0.233 V

oldschool2017-06-27T01:17:17Z

emf = N*d(BA)/dt
= 2*2.7*dA/dt
A = π*0.143² = .06424
dA/dt = .06424/0.49 = 0.1311
2*2.7*dA/dt = 0.708 V <----------