FIGURE 27-10
-A horizontal, long current-carrying wire is hanging from a vertical thread. The current is oriented into the plane of Fig. 27-10 shown above. A uniform magnetic field B = 0.4 T is applied along the negative y-axis and the wire is pulled and angle θ away from the vertical by a magnetic force. The wire has a length L = 80 cm, a mass m = 50 g and carries a current I = 0.3A. What is the value of the angle θ?

Question

FIGURE 27-10 
-A horizontal, long current-carrying wire is hanging from a vertical thread. The current is oriented into the plane of Fig. 27-10 shown above. A uniform magnetic field B = 0.4 T is applied along the negative y-axis and the wire is pulled and angle θ away from the vertical by a magnetic force. The wire has a length L = 80 cm, a mass m = 50 g and carries a current I = 0.3A. What is the value of the angle θ?

Quizplus · Accepted Answer

The magnetic force on the wire is given by F = ILB sin(θ), where I is the current, L is the length of the wire, and B is the magnetic field. The gravitational force is mg. At equilibrium, the magnetic force equals the horizontal component of the tension in the thread, and the gravitational force equals the vertical component. Solving for θ using tan(θ) = (ILB)/(mg), we find θ ≈ 11°.

FIGURE 27-10 -A Horizontal, Long Current-Carrying Wire Is Hanging from a Vertical