What is the kinetic energy of the electron in the nth level, moving in a plane under the influence of a magnetic field ' B '? [ m -mass of electron; h - Planck's constant; e- electronic charge]

A current loop consists of two identical semicircular parts each of radius $2 R$, one lying in the $x-y$ plane and the other in $x-z$ plane. If the current in the loop is I, the resultant magnetic field due to two semicircular parts at their common centre is

Two very long, straight, parallel wires carry steady currents I and 21 respectively. The distance between the wires is d . At a certain instant of time, a point charge $q$ is at a point equidistant from the two wires, in the plane of the wires. Its instantaneous velocity is v perpendicular to this plane. The magnitude of the force due to the magnetic field acting on the charge at this instant is

A charged particle is released from rest in a region of space in which steady and uniform electric and magnetic fields are parallel to each other. The particle will move in a