2.
如图所示,竖直放置的弯曲管\(a\)管封闭,\(d\)管开口,\(b\)、\(c\)管连接处有一关闭的阀门\(K.\)液体将两段空气封闭在管内,管内各液面间高度差是\(h\)\({\,\!}_{3} > \)\(h\)\({\,\!}_{1} > \)\(h\)\({\,\!}_{2}\),且\(h\)\({\,\!}_{3} < 2\) \(h\)\({\,\!}_{2}.\)现将阀门\(K\)打开,则会出现的情况是\(h\)\({\,\!}_{1}\) \((\)选填“增大”、“减小”\()\); \((\)选填“\(h\)\({\,\!}_{2}\)”、“\(h\)\({\,\!}_{3}\)”或“\(h\)\({\,\!}_{2}\)和\(h\)\({\,\!}_{3}\)”\()\)为零。