1、简答题  在半径为R的半圆形区域中有一匀强磁场，磁场的方向垂直于纸面，磁感应强度为B．一质量为m，带有电量q的粒子以一定的速度沿垂直于半圆直径AD 方向经P点（AP=d）射入磁场（不计重力影响）．
（1）如果粒子恰好从A点射出磁场，求入射粒子的速度．
（2）如果粒子经纸面内Q点从磁场中射出，出射方向与半圆在Q点切线方向的夹角为φ（如图）．求入射粒子的速度．

2、填空题  粒子（）和质子（）从静止开始经相同的电压加速后进入同一匀强磁场做圆周运动，则这两个粒子的动能之比为     ，轨道半径之比为      ，周期之比为      。

3、填空题  边长为a的正方形，处于有界磁场如图所示，一束电子以水平速度射入磁场后，分别从A处和C处射出，则vA：vC=__________;所经历的时间之比tA：tC=___________

4、简答题  如图所示，在倾角为θ，用绝缘材料制成的斜面上，一个质量为m，带电量为+q小滑块，它与斜面间的动摩擦因数为?（?＜tgθ）．整个装置处于方向垂直斜面向上，磁感应强度为B的匀强磁场中．若小滑块由A点静止释放，到达B点时刚好能做直线运动．已知斜面足够大，滑块电量不变，A、B两点高度差为H．
求：（1）试根据小滑块的受力特点，分析小滑块经过b点后的运动情况；
（2）小滑块作直线运动时的速度方向与斜面边线MN的夹角（用三角函数表示）；
（3）小滑块从A运动到B的过程中，滑动摩擦力所做的功．

5、选择题  人体缺锌会诱发疾病，检测人体中锌含量的一种方法是取人的头发在实验室中用中子照射，使中子和头发中的style="shiti/data:image/png;base64,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" alt="">进行核反应生成style="shiti/data:image/png;base64,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" alt="">，style="shiti/data:image/png;base64,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" alt="">衰变放射出γ射线，通过探测γ射线的强度可以计算出头发中锌的含量．针对以上叙述下列说法正确的是（　　）
A.style="shiti/data:image/png;base64,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" alt="">Zn衰变过程中存在质量亏损
B.style="shiti/data:image/png;base64,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" alt="">和style="shiti/data:image/png;base64,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" alt="">有相同的核子数
C．衰变生成的γ射线垂直射入匀强磁场时会发生偏转
D.2个style="shiti/data:image/png;base64,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" alt="">经过一个半衰期，一定有1个style="shiti/data:image/png;base64,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" alt="">发生衰变