真空中两块相互平行的无限大均匀带电平面A和B，A平面电荷面密度为
， B平面电荷面密度为
，两板间距离为a，当一点电荷q从A面移到B面时电场力作的功为：
A:
B:
C:
D:
， B平面电荷面密度为，两板间距离为a，当一点电荷q从A面移到B面时电场力作的功为：A:
B:
C:
D:
举一反三
- 下列汉字，不是会意字的有（ ）。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202004/3745c24ad6b741e1b0515f6f78732902.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202004/f2a234fa226e4c2283d973264d41a1cf.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202004/e727986add1f4513b034e96ba2a88137.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202004/5a95cc0dd6e64226a205a4ef6185f991.png" />
- 下列汉字中是象形字的有（ ）。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202004/8cecee6c952546deb3a1cefc3a98d641.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202004/7f6c55d56ebc4497913c8b2d9c761bf3.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202004/8f5a8473ecfe40a09b7f49bfea126107.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202004/cf93cf19ebae41d999f0229253098fe7.png" />
- 下列汉字，是指事字的有（ ）。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202004/a78009bbfc6443ad832d8ed215f9ec60.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202004/4ef5ae27ef2342e69844ef4cdd833c71.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202004/117a39b9b1bd4666b7c705a3868877b8.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202004/5635b12d2e9d479697bab0ec3e94eb4d.png" />
- 恒温恒压下，可逆反应达到平衡时，下列关系式正确的是： A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202004/14235e8fd11a44c89c953ff541fa1504.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202004/70016c166b8a47f19cfeba63da858e6f.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202004/f846aca457ea41bca91053f4d9d84449.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202004/e4b47257d5814e6fb45de9d47ee9965a.png" />
- 以下方程中能够说明磁场是非保守力场的是 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202004/c992e53d52334d1f8d60b01cfdbb942b.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202004/6b6bd95128d046b3adb3ff7af56f3920.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202004/cf765a59cc8a46cabc72150a545e54db.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202004/f588bc33929f49e9b0cecccdb0d164e1.png" />