Halliday, Resnick & Walker — Induction and Inductance: Problem 52

52 At a certain place, Earth’s magnetic field has magnitude \(B = 0.590 \text{ gauss}\) and is inclined downward at an angle of \(70.0^\circ\) to the horizontal. A flat horizontal circular coil of wire with a radius of \(10.0 \text{ cm}\) has 2500 turns and a total resistance of \(85.0\ \Omega\). It is connected in series to a meter with \(140\ \Omega\) resistance. The coil is flipped through a half-revolution about a diameter, so that it is again horizontal. How much charge flows through the meter during the flip?