如图所示，真空中的平行板电容器带有一定的电荷量Q，静电计的指针偏角为θ．若减小两极板的正对面积S，同时增大两极板间的距离d，关于极板间的电势差U及指针的偏角变化情况，下列说法中正确的是（ ）
A．U变小，θ变大
B．U变小，θ变小
C．U变大，θ变大
D．U变大，θ变小
由C=ɛ
可知，电容与正对面积成正比，与两板间的距离成反比；故减小正对面积、增大两极板间的距离时，电容器的电容减小；则由C=s 4πkd
可知，两板间的电势差变大；而指针偏角显示的是电势差的变化，故可知指角偏角变大；Q U
故选：C．
Which university would you like to go to in the future? It’s not too early to think about it right now.
Students at Hilltop School had a University Week at the end of last month. 小题1: For instance, they designed a flag for a virtual(虚拟的)“University of Hilltop”.
小题2: He said he started the program to help students form their aims. “University may not be for everyone, but we want the program to help students form their aims.” he said.
小题3: Eric, a student in Grade 8, said, “University Week made me realize that university is only four years away. I should do some research about where I want to go.” Paul, another student in Grade 8, said he realized that there so many universities for him to choose. 小题4:
The school also invited people to give career（职业）talks. The first talk was given by Captain Brown, a policeman. He talked about how to choose a career way.小题5:
“The program opened up the students’ eyes,” said Mr. Miller.
| A. According to the students, the program worked well. B. He also talked about the importance of math, reading, and writing in his career as a policeman. C. During the week, they took part in all kinds of activities. D. Mr. Miller is the teacher who started the program. E. Eric thinks it’s too early to think about which university to go to in the future now. F. After some research, he said he wanted to choose the University of California. |