A flat circular wire loop lies in a horizontal plane on a table and carries current in a counterclockwise direction when viewed from above.At this point,Earth's $\vec { B }$ field points to the north and dips below the horizontal.Which side of the coil tends to lift off of the table due to the magnetic torque on the loop?

Question

Quizplus · Accepted Answer

The magnetic torque on a current-carrying loop is given by the equation τ = NIA × B, where N is the number of turns in the loop, I is the current, A is the area of the loop, and B is the magnetic field. In this case, the magnetic field points to the north and is perpendicular to the plane of the loop, so A × B is in the east direction. The current in the loop is counterclockwise, so the magnetic moment is also in the east direction. The torque on the loop is then in the south direction, causing the south side of the loop to lift off from the table.

A Flat Circular Wire Loop Lies in a Horizontal Plane B⃗\vec { B }B

A Flat Circular Wire Loop Lies in a Horizontal Plane $\vec { B }$