benda berjarak 30 cm dari cermin cembung jarak fokus cermin 15 cm tentukan jarak bayangan dari tinggi bayangannya

cermin cembung (-)
1/s' = 1/f - 1/s
1/s' = 1/(-15) - 1/30
1/s' = -2/30 - 1/30
1/s' = -3/30
s' = -10 cm

M = |s'/s| = 10/30 = 1/3 kali

M = h'/h
1/3 = h'/h
h' = 1/3h