A flat circular wire loop of area 0.25 m² carries a current of 5.0 A.This coil lies on a horizontal table with the current flowing in the counterclockwise direction when viewed from above.At this point,Earth's $\vec { B }$ field is 1.2 × 10^-5 T directed 60° below the horizontal.What is the magnitude of the torque that Earth's magnetic field exerts on this loop?

Question

Quizplus · Accepted Answer

The torque on a current loop in a magnetic field is given by $\tau = nIAB \sin \theta$, where $n$ is the number of turns (1 in this case), $I$ is the current, $A$ is the area, $B$ is the magnetic field, and $\theta$ is the angle between the normal to the loop and the magnetic field. Here, $\theta = 60^\circ$, so $\tau = 1 \times 5.0 \, \text{A} \times 0.25 \, \text{m}^2 \times 1.2 \times 10^{-5} \, \text{T} \times \sin 60^\circ = 7.5 \times 10^{-6} \, \text{N} \cdot \text{m}$.

A Flat Circular Wire Loop of Area 0 B⃗\vec { B }B

A Flat Circular Wire Loop of Area 0 $\vec { B }$