如图所示的一细螺绕环，它由表面绝缘的导线在铁环上密绕而成，每厘米绕10匝．当导线中的电流I 为2．0 A时，测得铁环内的磁感应强度的大小 B 为1．0 T，则可求得铁环的相对磁导率<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/c31a3f1826e440f79e7fb4077c8b5656.png" />为（真空磁导率<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/6323a02b04c04433b348982bca792a04.png" />）（ ）<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/21646345be094027b95dfa1075514903.png" /> A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/d61b3d6b1b664ff7a7271955ea8cb90c.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/8599397fd0ad4c8a8ce382fc6eda4fd4.png" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/092b8a5debaa47f899b9745dba2a6492.png" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/6647d96f362c41879bd44d76722c7092.png" />

以下哪位是豫剧艺术家常香玉？ A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/dbd637c9af83424994f9aea4e8abc44a.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/02974b0beb3f433db263c281964e9dc0.jpg" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/12b7c600479849858f1cbfa120d2c863.jpg" />

如图所示，圆形截面区域内存在着与截面相垂直的磁场，磁感应强度随时间变化．磁场区域外有一与圆形截面共面的矩形导体回路 <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/0eea13cd51b54af3b701a0035e6416fe.png" />，以<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/865048ee310d46e09b743d6cfc93fa4a.png" />表示在导体<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/55379797515a41b88e0dcb947c44b585.png" />段上产生的感生电动势， I 表示回路中的感应电流，则（ ）<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/95d31735160f47dcb4d8f5ac973c0ce8.png" /> A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/986a62c34302465cad899f00080acc4f.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/4b6ab53aeebc4f92b722d8fff6237a87.png" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/d869de90826645c1b386e2019aa86be2.png" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/da8edb3a9af0442bb11dcee16f061375.png" />

设某微观粒子的相对论动量是它非相对论动量的<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/f04bc52895444aa9bf3ce69591507d4b.png" />倍，则其运动速度的大小为：（ c 表示真空中的光速）（ ）。 A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/39876687533246689c09bf2af4be1fe2.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/dd046c8367ec4635b34aaad5ceffe48b.png" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/99f25f4748cf434c96c5fa7552098ff5.png" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/85033bc491434663a83ffea2611f0c2b.png" />

要使<img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/c4b80714c3b14a559ae5bdcd09ef1fc6.png"/>是线性方程组AX=0的基础解系，则只要系数矩阵A=（ ）. A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/fb16cbefa5a746599e585bcf30dce878.png"/> B: ［2 1 1］ C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/df5d7a834bd44f44a519eaffffd47d39.png"/> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201804/5adacc7663b444d69f148ab2e7a11cf1.png"/>