Wire frame changing shape in magnetic field · CAP 2006 #10
Physics · electromagnetism
Problem
A uniform magnetic field B is directed out of the page. A metallic wire has the shape of a square frame and is placed in the field as shown. While the shape of the wire is steadily transformed into a circle in the same plane, the current in the frame:
(a) is directed clockwise;
(b) does not appear;
(c) is directed counterclockwise.