2)Sebuah benda terletak 12 cm didepan cermin cekung yang berfokus 4 cm jika tinggi benda 4 cm tentukan a.Jarak banyangan b.Perbesaran bayangan c.Tinggi banyanga

s = 12 cm
f = 4 cm
h = 4 cm

1/f = 1/s + 1/s'
1/4 = 1/12 + 1/s'
1/4 - 1/12 = 1/s'
(3-1)/12 = 1/s'
2/12 = 1/s'
s' = 12/2
s' = 6 cm

M = s'/s
M = 6/12
M = ½

M = s'/s = h'/h
½ = h'/4
h' = 4/2
h' = 2 cm