As shown in the figure below, a circular loop of radius a = 0.1 m lies in the horizontal x-y plane with its center located at the origin, with steady current I = 2.0 A circulating in a counter-clockwise direction in the loop. The magnetic field strength B(0,0,z) at the observation point (x, y, z) = (0, 0, 0.1 m) and its direction, due to the current I flowing in the circular loop is:
(a) B(0,0,z=0.1m) = 0.628 × 10-7 T, -z direction
(b) B(0,0,z=0.1m) = 2.323 × 10-6 T, +z direction
(c) B(0,0,z=0.1m) = 3.678 × 10-6 T, -z direction
(d) B(0,0,z=0.1m) = 4.443 × 10-6 T, +z direction
Answer is D
The Attempt at a Solution
I tried Ampere's law, but I am not sure what is B dot dl (especially angle) and what is the path in this case...