1/p+1/q=1/f
1/p+1/3p=1/18 (3倍之實像)
3/3p+1/3p=1/18
4/3p=1/18
3p=4×18
p=24
h:18=3h:a => a=54
h:所求=3h:(18+a),已知a=54=> 1:所求=3:72=> 所求=72/3=24
35。一焦距為18公分之凸透鏡,欲得實物3倍之實像,則其物距應為: (A)..-阿摩線上測驗