Jawabanmu

2014-05-12T18:59:03+07:00
1/jarak benda = 1/f - 1/jarak bayangan
1/jarak benda = 1/36 - 1/12
1/jarak benda = - 1/18
Jarak benda = -18 cm (perkalian silang)

Kalau cari tinggi benda,pakai persamaan Perbesaran (M)
M= Jarak bayangan : jarak benda
   = 12 : -18
   = - 2/3 kali

M= tinggi bayangan : tinggi benda
-2/3 = 9 : tinggi benda
Tinggi benda = 9 x - 3/2
=  -13,5 cm


2014-05-12T21:10:49+07:00
1/f = 1/s + 1/s.aksen
1/36 = 1/12 + 1/s.aksen
1/s.aksen = 1/36 - 1/12
1/s.aksen = -2/36
s.aksen = -18 (maya)
perbesaran = mutlak dari s' / s = -18/12 = 0,5

tinggi benda = h' / perbsrn = 9 / (0,5) = 4,5
atau cara : h'/h = s'/s --> h'/h = -18/12... h = h'/0,5 = 9/0,5 = 4,5