题目
题型:0122 同步题难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000440-22905.gif)
答案
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000440-23683.gif)
又r=
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000440-39310.gif)
由①②得v0=
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000440-24289.gif)
故电子要射出磁场,速率至少应为
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000441-74251.gif)
由③式可知,θ=0°时,v0=
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000441-14605.gif)
由②式知此时半径最小,rmin=
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000441-35890.gif)
核心考点
试题【匀强磁场的磁感应强度为B,宽度为d,边界为CD和EF。一电子从CD边界外侧以速率v0垂直射入匀强磁场,入射方向与CD边界间夹角为θ。已知电子的质量为m,电荷量为】;主要考察你对粒子在有界磁场中运动等知识点的理解。[详细]
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000432-44226.gif)
B.2∶1
C.1∶
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000433-28515.gif)
D.1∶1
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000412-62679.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000412-35029.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000413-26030.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000413-75480.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000413-20973.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000413-33354.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000413-29915.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000413-44764.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000414-41358.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000414-93883.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000414-26313.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000414-52430.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000415-50855.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000415-94341.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000415-20775.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000415-31139.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000415-17096.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000416-84866.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000416-54840.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000416-25222.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000416-31496.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000416-97640.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000417-42150.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000417-13434.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000417-69062.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000417-96852.gif)
(1)求在区域Ⅰ和Ⅱ中粒子运动速度
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000418-47486.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000418-48521.gif)
(2)求在区域Ⅰ和Ⅱ中磁感应强度
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000418-62791.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000418-15244.gif)
(3)若上述两个磁场保持不变,荧光屏仍在初始位置,但从
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000418-65503.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000419-25471.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000419-40274.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000419-81533.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000419-90951.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200115/20200115000420-51247.gif)
B、带电粒子飞入匀强磁场后做匀速圆周运动时,速度一定不变
C、带电粒子飞入匀强磁场后做匀速圆周运动时,洛仑兹力的方向总和运动方向垂直
D、带电粒子飞入匀强磁场后做匀速圆周运动时,动能一定保持不变
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