An infinitely long cylinder, radius a, carries a current I, distributed uniformly over its cross-sectional area. The axis of the cylinder coincides with the z-axis.
a) Calculate the force per unit length exerted by the y > 0 half of the cylinder on the y < 0 half of the cylinder.
b) Is the force attractive or repulsive?
c) What is the magnitude of this force for a one meter length of wire 1 mm in diameter carrying a current of 10 A?