Force on currents: A wire segment 1.2 m long carries a current I = 3.5 A, and is oriented as shown in the figure. The +x-axis points directly into the page. A uniform magnetic field of magnitude 0.50 T pointing toward the -x direction is present as shown. What is the magnetic force vector on the wire segment?

Question

Quizplus · Accepted Answer

The magnetic force vector on a current-carrying wire is given by the equation F = I L B sinθ, where I is the current, L is the length of the wire segment, B is the magnetic field strength, and θ is the angle between the wire and the magnetic field. In this case, the wire segment is perpendicular to the magnetic field, so sinθ = 1. Plugging in the values, we get F = (3.5 A)(1.2 m)(0.50 T)(1) = 2.1 N. The force is directed in the -x direction because the magnetic field is pointing in the -x direction and the current is moving in the opposite direction (from right to left). The force vector therefore has components of (-1.8 N, 1.1 N, 0 N) in the (x, y, z) directions, respectively. The answer that matches these components is D.

Force on Currents: a Wire Segment 1