在下列条件下,两种气体的分子数一定相等的是( )
A:同质量、不同密度的N2和C2H4
B:同温度、同体积的O2和N2
C:同体积、同密度的CO和CH4
D:同压强、同体积的N2和O2
如图所示,直角三棱镜置于空气中,已知∠A=60°,∠C=90°,一束极细单色光从AC的中点D垂直AC面入射,AD= 6 m,棱镜对该单色光的折射率n= 2 ,求:
The news came, as expected, __________ my cousin was chosen to be a foreign aid doctor to go to Africa where people are suffering a lot from aids.
引起大气运动的根本原因是( )