问题 选择题
在匀强磁场中有一个原来静止的碳14原子核,它放射出的粒子与反冲核的径迹是两个相内切的圆,如图所示.那么碳14的衰变方程为(  )

A.+

B.+

C.+

D.+

答案

答案:D

开放性试题

在我国西部边远山区,仍然有许多孩子因为家庭贫困以及家庭距离学校过远等原因不能完成规定的九年义务教育。

(1)请谈谈你对部分边远山区学生辍学行为的看法?

                                                                                                                                                              

                                                                                                                                                              

                                                                                                                                                              

(2)针对上述情况,你所在的学校准备开展一次爱心活动。你会怎样向全校同学发出倡议?请完成该倡议书的内容。

①标题《________________________________________________》

②称呼:尊敬的各位同学

③正文:__________                                                                                                                             

                                                                                                                                                            

                                                                                                                                                           

                                                                                                                                                           

                                                                                                                                                            

单项选择题