同济大学：《大学物理》课程教学资源（电子教案，英文版）第十五章 磁场（上）

Magnetic field

Magnetic field

Agenda today 1.Magnetic force on a moving charge 2.The motion of single charge in magnetic field 3.Magnetic force on current 4.The Hall effect

Agenda today 1. Magnetic force on a moving charge 2. The motion of single charge in magnetic field 3. Magnetic force on current 4. The Hall effect

Magnet and Magnetic Field North pole and South Pole N Magnetic Field B

Magnet and Magnetic Field N S North pole and South Pole Magnetic Field B

Magnetic force on an electric charge FB=qV×B B The magnitude of the force is: 分q6 In SI unit,1T=1kg/(C.s) 1G=104T

Magnetic force on an electric charge + B  v Fmax In SI unit, 1T=1kg/(C·s) G T 4 1 10  The magnitude of the force is:

Lorenz Force E×B The magnitude of the magnetic field is: B= max The direction of magnetic field is that of

The magnitude of the magnetic field is: qv F B max  The direction of magnetic field is that of F v   max  Lorenz Force

Motion of electric charge in magnetic field 1 The circular motion v2 qvB=m R B The radius mv R= X 9B

Motion of electric charge in magnetic field 1 The circular motion F R                                           + v B R v qvB m 2  qB mv R  The radius

11-6离子比荷的测定 0113 m1<m2<m3.12 1 加速电场 速度选择器「 A 底片 × XX XXXXXX X ××X×X×X× 4 提示：单击鼠标射出下一个粒子

The period of the 2元R 2n m motion 7、 v gB The cyclotron frequency 1 qB T (回旋频率) 2n m The cyclotron period and frequency are independent of speed

qB m v R T 2 2   The period of the motion m qB T   2 1   The cyclotron frequency The cyclotron period and frequency are independent of speed. （回旋频率）

Cyclotron(回旋加速器) ××××X× XX XX XX XXX 加速器结构图

Cyclotron（回旋加速器）

2 The helical motion V21 B The pitch of helix h=ur=2rm vcos0 gB

2 The helical motion B v 1 v 2 h  + v The pitch of helix   cos 2 1 v qBm h  v T 