A circular loop of radius R1 lies in the x y plane, centered on the origin, and has a current i running through it clockwise when viewed from the positive z direction. A second loop with radius R2 sits above the first, centered on the positive z axis and parallel to the first.

1. If the second loop is centered at the point z = R1, what must the current be (direction and magnitude) in order for the net magnetic field at the center of the first loop to be zero.

a. Assume the following values for your answer: i = 2 ampere, R1 = 10 centimeter and R2 = 5 centimeter. What is the magnitude of the current? Give your answer in ampere.