Question

如图所示，边长为l的正方形区域abcd内存在着匀强电场．质量为m，电荷量为q的带电粒子以速度v₀从a点进入电场，恰好从c点离开电场，离开时速度为v，不计重力，求电场强度．                             

                                                                                                  

                                                                                                                                 

Answer 1

解：带电粒子在匀强电场中只受电场力，电场力F=qE，

带电粒子沿电场方向的位移等于l，

所以电场力做功W=Fl=qEl．

根据动能定理W=△E_k

即qEl=

解得E=

答：该电场强度为．