Final answer:
The question asks about an armature, which is supported by bushings or ball bearings, and allows it to rotate. An armature interacts with a magnetic field in devices such as electric motors and meters.
Step-by-step explanation:
The student's question pertains to a component commonly found in electric motors and meters, known as an armature. Inside the field coils is an armature that is supported with either bushings or ball bearings at both ends, which permit it to rotate. The armature is a critical part of an electromagnetic apparatus where it interacts with the magnetic field to create motion in motors, or to measure current in meters. Field coils create a magnetic field, and the armature, being within this field, experiences a force and thus can rotate when electrical current passes through it. This is a fundamental concept in understanding how electromagnetic devices function.
Including references to devices such as the flip coil and the uniformity of the magnetic field within certain apparatuses helps in relating the practical applications of an armature in creating motion or measuring electromagnetic variables.