Two current loops are coaxial and coplanar.One has radius a and the other has radius 2a.Current 2I in the outer loop is antiparallel to current I in the inner loop.The magnitude of the magnetic field at the center of the two loops is
A)0.
B) .
C) .
D) .
E) .

Question

Two current loops are coaxial and coplanar.One has radius a and the other has radius 2a.Current 2I in the outer loop is antiparallel to current I in the inner loop.The magnitude of the magnetic field at the center of the two loops is
A)0. 
B) . 
C) . 
D) . 
E) .

Quizplus · Accepted Answer

By applying Biot-Savart's law, the magnetic field at the center of a current loop is given by B = μ0 I/2R, where μ0 is the magnetic constant, I is the current in the loop, and R is the radius of the loop. Since the two loops have opposite currents and are coaxial, the magnetic fields due to each loop cancel each other out at the center, resulting in a net magnetic field of 0.

Two Current Loops Are Coaxial and Coplanar