A coil is wrapped with 239 turns of wire on the perimeter of a circular frame (radius = 9 cm). Each turn has the same area, equal to that of the frame. A uniform magnetic field is turned on perpendicular to the plane of the coil. This field changes at a constant rate from 15 to 81 mī in a time of 19 ms. What is the magnitude of the induced emf (in Volts) in the coil at the instant the magnetic field has a magnitude of 50 mT?

A circular coil (670 turns, radius = 0.079 m) is rotating in a uniform magnetic field. At t = 0 s, the normal to the coil is perpendicular to the magnetic field. At t = 0.020 s, the normal makes an angle of 45 degrees with the field because the coil has made one-eighth of a revolution. An average emf of magnitude 0.052 V is induced in the coil. Find the magnitude of the magnetic field at the location of the coil.

A circular loop of wire lies in a plane perpendicular to a magnetic field. The magnetic field has a magnitude of 1.3 T and points out of the page as shown in the figure. The radius of the loop is 18 cm and it has a resistance of 3.2 Ω. Find the induced emf in the loop of wire if the magnetic field doubles in magnitude in 1 seconds. What is the induced current in the loop? In which direction is the induced current?

A coil formed by wrapping 55 turns of wire in the shape of a square is positioned in a magnetic field so that the normal to the plane of the coil makes an angle of 36.0° with the direction of the field. When the magnetic field is increased uniformly from 200 µT to 600 µT in 0.400 s, an emf of magnitude 80.0 mV is induced in the coil. What is the total length of the wire? m