A copper disk of radius 10 cm rotates in a uniform magnetic field, making 100 revolutions per second (figure). The magnetic field induction perpendicular to the plane of the disk is 1 Tesla. Two brushes, one on the axis of the disk, the other on the periphery, connect the disk to an external circuit, including a rheostat with a resistance of 10 Ohms and an ammeter, the resistance of which can be neglected, like the resistance of the disk itself. What does the ammeter show?

Answer. Format gif