《带电粒子在磁场中的运动》专题训练（Special training on the motion of charged particles in the magnetic field）.doc

《带电粒子在磁场中的运动》专题训练（Special training on the motion of charged particles in the magnetic field） Special training on the motion of charged particles in the magnetic field Class: ____________ name: MAO yonghui review: lu lijin Charged particles into the vertical uniform magnetic field, the magnetic field for uniform circular motion of the test questions are common in the examination of all types and at all levels, points rate is high, the main reason for the loss of marks is cant find the center of the circle, unable to draw the trajectory accurately, below is the magnetic field for circle, draw the trajectory of the common methods. Basic knowledge 1. Lorentz force provides centripetal force: Radius of movement; Exercise cycle: 2. When calculating radius, two important geometric features should be grasped: (1) bias Angle Φ equal to swing Angle alpha particles, and is equal to the rotation and the tangent of the Angle (rotary Angle theta) 2 times, as shown in the picture on the right: Φ = alpha theta equals omega t = 2 (2) the relative rotation Angle theta is the same. 3. Movement time (Angle system), (radian) 4. Symmetry rules in circular motion: (1) when a particle is ejected from the same boundary, the Angle of the velocity is equal to that of the boundary when it is emitted from the same boundary. (2) in the circular magnetic field region, the particles in the radial direction will shoot along the radial direction. 5. The condition that the boundary of the uniform magnetic field is just worn is that the trajectory is tangent to the boundary. 6. The larger the arc length (or the long), the longer the movement time in the magnetic field. The direction of incident and the direction of the shooting direction are known to determine the center of the circle The direction of lorentz force on the two points of the circle movement will be the center of the extension. Known when the direction of the incident direction and exit through the point of incidence and exit point perpe