Chapter 19 - Magnetism - Learning Path Questions and Exercises - Conceptual Questions - Page 690: 25

The direction of the current should be counterclockwise to cancel the magnetic field of the outer loop. Its current has to be smaller than 10A, since the field created by a loop is inversely proportional to radius of that loop. With a smaller radius for inner loop, its current must be less than 10A.

The direction of the current should be counterclockwise to cancel the magnetic field of the outer loop. Its current has to be smaller than 10A, since the field created by a loop is inversely proportional to radius of that loop. With a smaller radius for inner loop, its current must be less than 10A.