A flat circular coil of N turns, area A, and resistance R is placed in a uniform magnetic field B. The plane of the coil is initially perpendicular to B. When the coil is rotated through an angle of 180∘ about one of its diameters, a charge q1 flows through the coil. When the same coil, after being brought to its initial position, is rotated through an angle of 360∘ about the same axis, a charge q2 flows through it. Then q2/q1 is
(a) 1
(b) 2
(c) 1/2
(d) 0