阅读。选择题,将正确答案的字母写在括号内。
I am Alice. We(我们) are in the playground(操场). We are playing football(踢足球). We are thirsty(口渴的). We are drinking. I like cola. Tom likes milk. Peter likes juice. Eddie likes water. We are happy.
如图所示,虚线框内有匀强电场,AA,、BB,、CC,是该电场的三个等势面,相邻等势面间的距离为0.5cm,其中BB,为零势面。一个质量为m,电量为q的粒子沿AA,方向以初动能EK自图中的P点进入电场,刚好从C,点离开电场。已知PA,=2cm,粒子的重力忽略不计,下列说法正确的是( )
如图所示,早晨的太阳光斜射到一块水平放置的平面镜上,经镜面反射后,反射角为 ____ ,随着时间的推移,从早晨到中午,反射角将 ____(选填“增大”、“不变”或“减小”).