Desperately need help with both parts of this problem. Thank you so much!
3. A circular loop of thin wire (with radius a) is centered on the origin, sitting in the x-y plane, and carries a steady current I in the counterclockwise direction (i.e. from the positive x-axis toward the positive y-axis). At the same time, another circular loop of thin wire (with radius 2a) is centered on the origin, sitting in the x-y plane, and carries a steady current I in the clockwise direction.
a) Using the Biot-Savart law, find the total magnetic field at the origin. (Hint: Find the magnetic field at the origin due to each loop, then vector sum both of these fields to get the total field. Don't forget that the separation vector extends from the source point to the observation point.)
b) What would I have to be in order for there to be exactly zero magnetic field at the origin?
