问题 选择题

把一个正电荷由电场中A点移到无限远处,电荷克服电场力做功3×10-4J,把一个等量的负电荷由电场中B点移到无限远处,电场力做功5×10-4J。以无限远处为零电势,则A、B两点电势关系是                          (    )

A.φAB>0    B.φAB<0     C.φBA>0     D.φBA<0

答案

答案:D

综合

图为我国旱涝灾害分布示意图,读图分析回答下列各题。

(1)我国旱涝灾害分布规律及其原因是________________________________________________________

    _________________________________________________________________________________________

    _________________________________________________________________________________________

    _________________________________________________________________________________________

    _________________________________________________________________________________________

    ___________________________________________________________________。

(2)图中A地洪涝灾害多发的月份是____________,从大气环流角度分析原因是_____________________

    _______________________________________________________________________________________;

    旱灾多发的月份是,形成的原因是___________________________________________________________

    ____________________________________________________________。

(3)B地旱涝灾害频繁对当地农业生态环境有什么影响?可采取哪些对策?

    _________________________________________________________________________________________

_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________。

判断题