1 . 如图所示的坐标系中,第一象限内存在与x轴成30°角斜向下的匀强电场,电场强度;第四象限内存在垂直于纸面向里的有界匀强磁场,y轴负方向无限大,磁感应强度
。现有一比荷为
的正离子(不计重力),以速度
从O点垂直磁场射入,
,离子通过磁场后刚好直接从A点射出,之后进入电场。求:
(1)离子从O点进入磁场B中做匀速圆周运动的半径R;
(2)离子进入电场后经多少时间再次到达x轴上;
(3)若离子自O点进入磁场B运动到某一特殊位置时,再加一个垂直纸面向里的同方向的匀强磁场使离子做一个完整的圆周运动,然后磁场再恢复到初始数值以使粒子仍能从A点射出,求所加磁场磁感应强度
的最小值。
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/515687169e0d696e17ac4b93192d8c48.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3cae4037ed1f5c70c14310b2974b807e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6b86c22b670a8e9f3896f9e8883fbbb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f58888df91890a19a1aa7511d19703f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6b86c22b670a8e9f3896f9e8883fbbb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b78a0ba96101f1240cceb65d63595d9.png)
(2)粒子从A点运动到
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/485005491d5b5e43b963cf55bd7c2a74.png)
(3)匀强磁场的磁感应强度与匀强电场的电场强度的比值
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/722386e498a172f12ddf7a7dbdb84de2.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/19/be968594-9443-43d3-bd4e-794a9c2f673e.png?resizew=328)
3 . 如图所示,在平面直角坐标系xOy中,第I象限内存在匀强电场,电场方向沿y轴负方向,第Ⅱ象限内存在垂直于xOy平面、半径为R的有界圆形匀强磁场,边界线与x轴相切于A点、与y轴相切于M点,第Ⅳ象限存在矩形边界的匀强磁场(图中未画出),第Ⅱ、Ⅳ象限匀强磁场的磁感强度大小相等、方向相反。有一电荷量为q、质量为m的带正电的离子从P点(,
)以初速度
向着圆心方向射入磁场,从M点进入电场,从x轴上的
(
,
)点进入第Ⅳ象限矩形边界的匀强磁场内,经磁场偏转后,粒子打到-y轴上的Q点时速度方向与
轴成45°角,粒子重力不计。求:
(1)匀强磁场的磁感应强度和匀强电场的电场强度分别为多大;
(2)第Ⅳ象限内矩形磁场面积的最小值。
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/707235bc08ffb9c03056595831cf251e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa8a716a31b0f51b70fdf9bdb257909.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f58888df91890a19a1aa7511d19703f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/903c1bb6f9fe8f9b9710683a3e601452.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c687a6c2bdbed49d6b8b8574444736a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdfaebfbc8951d804adeb6980627b38e.png)
(1)匀强磁场的磁感应强度大小
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
(2)匀强电场的电场强度大小
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
(3)粒子在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
(4)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
5 . 如图所示,在平面内,第Ⅱ象限内的射线
是电场与磁场的分界线,
与
轴的负方向成
。在
且
的左侧空间存在着垂直纸面向里的匀强磁场B,磁感应强度大小为
,在
且
的右侧空间存在着沿
轴正方向的匀强电场
,场强大小为
。一不计重力的带负电微粒,从坐标原点
沿
轴负方向以
的初速度进入磁场,最终离开磁、电场区域。已知微粒所带的电荷量
,质量
,求:
(1)带电微粒在磁场中做圆周运动的半径;
(2)带电微粒第一次进入电场前运动的时间;
(3)带电微粒第二次进入电场后在电场中运动的水平位移。
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f015b8b2aacd0512fb5e1b282952662f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa8a716a31b0f51b70fdf9bdb257909.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f58888df91890a19a1aa7511d19703f.png)
(1)粒子在Ⅱ区域匀强磁场中运动的轨道半径;
(2)匀强磁场区域OP的宽度;
(3)粒子从M点出发到第一次速度变为0所经历的时间。
![](https://img.xkw.com/dksih/QBM/editorImg/2023/10/26/b339f02d-4b42-4bb4-adec-f5a1254e73f5.png?resizew=241)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e2095b0a336ae937297fedf99b3a5d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e2095b0a336ae937297fedf99b3a5d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45049737f8cc679228ebc6f1abe2efb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/696305586b6c77d707b661a5ffdb7efb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a06cec503d48d613eeff819b95bb0afd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/640616423c74fff7b7a8568ad4e7453c.png)
(1)圆形磁场区域内的磁感应强度的大小;
(2) 粒子经过边界
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/28102fce05604c1d7dc92d74f8240d46.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd3b9e816b14051f785aa5aae72b8eed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7334235a057dcfe4843f96cb25ad93d8.png)
(3) 粒子整个运动过程中,轨迹最左端离边界
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5e2095b0a336ae937297fedf99b3a5d5.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/23/1c604844-7184-40d5-bfcd-08b508df68ee.png?resizew=305)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69c8eaf14b651bd74e098546c174d1de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0caabffc3d2e095064135b8220ca8484.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad09d822c4d0d9e25a57cad0964fa3c4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca4ff0af96ea467337cb30c4c765b5f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c88d9142df6ba8e43c1a93bd04a1362.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e6489f2e2cd348d50da7e44ff17434d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8cee293a3b75c9365b9cbfcc5a62d366.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ee5bdd975db3e059ffb9e5568b8f626.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa8a716a31b0f51b70fdf9bdb257909.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d9621cb015e5563d66d4b5270e1954a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f384e98d574fa2676d61624285f88188.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca4ff0af96ea467337cb30c4c765b5f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fa992111a6eb3b3eaa54a65d3dfb9f90.png)
(1)求两金属板间磁感应强度
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a68a83260d4f112c35d03b237d68a54.png)
(2) 求dh连线下方空间电场强度 E的大小;
(3) 将
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ee5bdd975db3e059ffb9e5568b8f626.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0aa31339cc786ca3c1eb48ccc5119805.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0dff5a4d8394b4ac7131843f72b86cd.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/16/0bdc05ae-23e1-4c35-a6c7-807ef0d77934.png?resizew=247)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4aaab013c25b014549fd0675c2b34df1.png)
(1)若从S发出的带电粒子经磁场偏转一次就能到达A点,求粒子的最小速度
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f58888df91890a19a1aa7511d19703f.png)
(2)若从S发出的带电粒子的初速度方向与竖直方向的夹角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d7b9d9bf0d5fc25c99170ab27fa4045.png)
(i)求匀强电场的电场强度大小E;
(ii)求粒子的运动周期T。
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/13/25508775-774f-4c5e-a733-51da842c9389.png?resizew=222)
(1)粒子在磁场区域运动的轨迹半径r;
(2)粒子在磁场区域运动的时间;
(3)粒子打在y轴上离原点O的最远距离d。
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/12/bfff2294-2d4b-4ab3-ac5c-679e39e9e395.png?resizew=194)