A Toroid Is Made of 2 000 Turns of Wire

Multiple Choice

A toroid is made of 2 000 turns of wire of radius 2.00 cm formed into a donut shape of inner radius 10.0 cm and outer radius 14.0 cm. When a 30.0-A current is present in the toroid, the magnetic field at a distance of 11.0 cm from the center of the toroid is

A) 0.0857 T.
B) 0.109 T.
C) 0.120 T.
D) 0.600 T.
E) 0.685 T.