Question

A wire is bent into the shape of a circle. The radius

of the circle is 17 cm. A constant magnetic field

of magnitude 1,9 T is directed perpendicular to

the plane of the paper. Someone grabs the ends

of the wire and pulls it out, so the radius of the

circle shrinks to zero in a time of 1,7 s. Find the

magnitude of the average induced emf between the

ends of the wire.