单项选择题
A parallel-plate capacitorwith area A and separation d is filled with a dielectric medium of relative permittivity (dielectric constant). The capacitor is being charged at a constant rate dV/dt. Here V is the potential difference between the two plates of the capacitor. The displacement current between the plates is . A、 B、 C、 D、
单项选择题 （ ）一般设置在入口处附近，以别出心裁的设计吸引顾客，切忌平面化；也可以通过一些生活化场景使顾客感到亲切自然，进而产生共鸣。 A. 橱窗 B. 展示区 C. 收银台
多项选择题 哪些单胞（cell）必须只含一个基元？ A、固体物理学原胞 B、维格纳-赛兹原胞 C、结晶学原胞 D、晶胞 E、倒格子原胞 F、第一布里渊区
(dielectric constant). The capacitor is being charged at a constant rate dV/dt. Here V is the potential difference between the two plates of the capacitor. The displacement current between the plates is .
