如图所示，将电动势为E，内阻r的电源接在AB之间．当开关S接通后（  ）

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SQL Error: select id,body,options from ***_enewstiku_ where sourceid='15523' and id < 2637963 and id<>'2637963' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='15523' and id > 2637963 and id<>'2637963' order by id asc limit 5