sebuah benda setinggi 10 cm diletakkan 20 cm didepan cermin cekung yang jari-jari kelengkungannya 60 cm Tentukan jarak bayangan perbesaran bayangan tinggi bayan

f = R/2 = 60/2 = 30 cm
1/s + 1/s' = 1/f
1/20 + 1/s' = 1/30
1/s' = -1/60
s' = -60 cm ⇒ di belakang cermin

M = s'/s
M = 60/20
M = 3 kali ⇒ Jawab

diket : ho = 10cm
so = 20cm
r = 60cm
f = 0,5*60 =30cm
dit : a) si
b) M
c) hi
jawab :
a) 1/f = 1/so + 1/si
1/30= 1/20 + 1/si
1/si = 1/20 - 1/30
1/si = 3/60 - 2/60
si = 60/1
si= 60 cm
b) M = si/so
M = 60/20
M = 3
c) M = hi/ho
3 = hi/10
hi = 3 * 10
hi = 30 cm