来自李长生的问题
Whichstatementabouttheimageformedbyathinconverginglensiscorrect?AitisalwaysrealanderectBitisalwaysrealandinvertedCitisalwaysvirtualanderectDitmaybeeithervirtualorreal给出原因.（好像是分小于f,f与2f之
Whichstatementabouttheimageformedbyathinconverginglensiscorrect?
Aitisalwaysrealanderect
Bitisalwaysrealandinverted
Citisalwaysvirtualanderect
Ditmaybeeithervirtualorreal
给出原因.（好像是分小于f,f与2f之间,大于2f三种情况,f是焦距）
