【判断题】2009年7月,在意大利召开的八国首脑会议上,认可了地球平均气温升高限值为2℃的控制目标。( )
【简答题】采用测距三角高程方法测得某点的平距为637.100m、垂直角为00,量得仪器高、目标高分别为1.500m、1.200m,设地球半径、大气垂直折光系数分别为6371km、0.14,可求得高差为()。
【单选题】What is the main idea of the passage?
A.
Most old people live longer today after an illness than people did years ago.
B.
Many old people are put into nursing homes by their families, who do not visit them regularly.
C.
Most elderly people are taken care of by their families, who assume the responsibility for different reasons.
D.
Most elderly people are satisfied with the better ways of caregiving that social workers have come up with.
【简答题】试证若认为地球的大气是等温的,则把所有大气分子压缩为一层环绕地球表面的、压强为一个大气压的均匀气体球壳,这层球壳厚度就是大气标高.
【简答题】若把地球大气看作温度恒定为 K 的等温大气层 , 用 和 分别表示地表的压强和地球半径 ;(1) 定义 为地球大气标高 , 试求此标高的数值 , 并对此标高的物理意义作出解释 ;(2) 试给出地球大气层总粒子数 的计算公式 , 并 (3) 求出地球大气总粒子数 和总质量