Question 5. An infinite straight wire with a circular cross-section of radius R is lying along the z axis and it has an internal field given by: Jo 1 # = 10 (½ sin (ar) — — cos(ar) & r a² where r is the radial distance from the centre of the circular conductor, & is the azimuthal unit vector, Jo is a constant current density, and a = π/(2R). Find an expression for the total free current If in the conductor, and give its direction.

Question 5. An infinite straight wire with a circular cross-section of radius R is lying along the z axis and it has an internal field given by: Jo 1 # = 10 (½ sin (ar) — — cos(ar) & r a² where r is the radial distance from the centre of the circular conductor, & is the azimuthal unit vector, Jo is a constant current density, and a = π/(2R). Find an expression for the total free current If in the conductor, and give its direction.