输电线路单位长度的电感和电容分别为、，则波速大小为（）。

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SQL Error: select id,body,options from ***_enewstiku_ where sourceid='10752' and id < 857618 and id<>'857618' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='10752' and id > 857618 and id<>'857618' order by id asc limit 5