填空题。Part of a wire is bent into a semicircle of radius \(R\). The wire lays in the \(xy\) plane and carries a current \(I\). A uniform magnetic field \(\vec{B}\) is directed along the \(z\) axis. What is the magnitude of the magnetic force on the curved portion of the wire? \_\_\_\_\_\_
填空题。Part of a wire is bent into a semicircle of radius \(R\). The wire lays in the \(xy\) plane and carries a current \(I\). A uniform magnetic field \(\vec{B}\) is directed along the \(z\) axis. What is the magnitude of the magnetic force on the curved portion of the wire? \_\_\_\_\_\_
发布时间：2026-03-01 16:15:20
