Please answer the following 3 problems with work. Thank you

Problem 6: Consider two parallel infinite planes, as shown in Figure 6. In one of the planes there is a surface current density g and there is no net charge. In the other plane there is no current, but it is assumed that there is a surface charge density o. Between the two planes travels a charged particle with electric charge q, whose speed (v) is perpendicular to the current density g. Knowing that the total force on the particle is zero (and there is no gravity), calculate the charge density o. Option A: 2 C/cm2 Option B: 12.12 x 109 C/m Option C: 12.12 x 10-9 C/cm Option D: 0 Problem 7: Consider two parallel cables like those shown in the Figure 7. In one of them there is a current of 1 A and in the other there is a current of 2A. It is requested to calculate the distance x of the first cable (see the Figure 7) such that, there, the magnetic field is zero. Option A: 1/3 m Option B: 1/2 m Option C: 0.75 m Option D: 10 cm Problem 8: Consider an infinitely long conducting cylinder and, within it, an infinitely long wire housed in the axis of symmetry of the cylinder. In the cylinder wall there is a surface current density g and, in the wire, there is a current I (see Figure 8). If it is known that the absolute value of the magnetic field at a distance of 2m from the cable is 4T, what is the absolute value of the magnetic field at a distance of 4m from the cable?. Option A: 1 T Option B: 2 T Option C: 4 T Option D: 0.04 T