如图所示，两个同心的均匀带电球面，内球面带电荷Q1，外球面带电荷Q2，则在两球面之间、距离球心为r处的P点的场强大小E为
A:
B:
C:
D:
A:
B:
C:
D:
举一反三
- 如图所示电路的逻辑表达式F=（ ）。<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/8655693a417e4e43a32e0732ed533c96.png" /> A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/beda73211aea49f082d9137fd4eb0526.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/7388c99ee0824f20bcf85893934a2f6a.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/9a5c81e78b344c79a9389e932a7f55ce.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/82193a9a030243728012b02e15718987.png" />
- 某反应在标准态和等温等压条件下，在任何温度都能自发进行的条件是（ ）。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/63c6a7b5b3114c1095cb68d96ebd27ec.png" />< 0，<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/d11dd437fcbe440d886e25a9a04f2c0e.png" />> 0 B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/63c6a7b5b3114c1095cb68d96ebd27ec.png" />> 0，<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/d11dd437fcbe440d886e25a9a04f2c0e.png" />> 0 C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/63c6a7b5b3114c1095cb68d96ebd27ec.png" />> 0，<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/d11dd437fcbe440d886e25a9a04f2c0e.png" />< 0 D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/63c6a7b5b3114c1095cb68d96ebd27ec.png" />< 0，<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/d11dd437fcbe440d886e25a9a04f2c0e.png" />< 0
- 如右图所示拉杆头的挤压面积为( )。<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/7ddd21a3a4e849f68c4d176b971c7c55.png" /> A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/df97de243a424ac58b1dc7cb70374683.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/eab41cb13f55410ea57bc67fbf155a7b.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/8c54a383f7e8426eb0f0f7c435a433ba.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/9120d45143384f29aef7b86ea444f7f3.png" />
- 电路如图所示。则u01、u0与 uI的运算关系分别为（ ）、（ ）。 <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/418adfb996644706aef30b7d2841ccb9.png" /> A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/ffe4934c2b0748428937c24c7ff16c3b.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/1da45f59ab0845f7be8cdc1f80a78caa.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/ca685a45d5764329b8551eb6eaeb6a58.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/d3f91ade92954e7fbd65a917b04cc13b.png" />
- 已知某网络函数单位冲激响应如图所示，则网络函数表达式可能为（ ） 。<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/1ea32deea3ff4a79adbdf2fd1d50f685.png" /> A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/3daa0643dbc0480582ecdded649049b2.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/38da044f0efb404a840b6cad69f53996.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/97e060f9767b46cbaa03ec6a04f8baed.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/fc42e852a3ca49ff9fcb9d5efe69a1a9.png" />