Question

A current loop lies in the xy plane of an xyz coordinate system, with the current circulating counterclockwise when viewed looking down the positive z axis toward the origin. The loop experiences a torque about the x axis that is counterclockwise when viewed looking down the positive x axis toward the origin. Part A Describe the direction of the uniform external magnetic field responsible for this torque. Describe the direction of the uniform external magnetic field responsible for this torque. The magnetic field is in the positive y direction. The magnetic field is in the negative x direction. The magnetic field is in the positive x direction. The magnetic field is in the negative y direction. The magnetic field is in the positive z direction. The magnetic field is in the negative z direction. Request Answer

Answer 1

Answer:

Magnetic field must be in YZ plane except in negative and positive Z direction.

Explanation:

Here loop is in XY plane and current direction as defined then its magnetic moment is in negative Z direction.

• So to rotate loop about X axis force should be in plane YZ.

• Thus torque produced by this magnetic force is in direction of X axis.

Now we know torque on a loop is calculated by

Torque=magnetic moment × B (vector cross product)(Here B is magnetic field)

Thus magnetic field can be in  the positive and negative Y direction and Z direction.

diagram is in attachment.