The current density inside a long, solid, cylindrical wire of radius a = 3.4 mm is in the direction of the central axis and its magnitude varies linearly with radial distance r from the axis according to J = J0r/a, where J0 = 300 A/m2. Find the magnitude of the magnetic field at a distance (a) r=0, (b) r = 2.6 mm and (c) r=3.4 mm from the center.

Ten students stand in a circle and are told to make a transverse wave. what best describes the motion of the students? each student bumps the shoulder of his or her neighbor. at the exact time, all students take a step to the right. the students skip clockwise, going in a circular motion. one at a time, each student lifts his or her hands up and then down.

When an object is heated it contracts. a. true b. false

Four friends, a, b, c, and d are standing varying distances away from a speaker which is producing sound waves.