Benda setinggi 4 cm ditempatkan 5cm di depan lensa cembung. apablia jarak fokus lensa 10cm, bayangan yang terbentuk setinggi...cm a.4 b.8 c.10 d.20

ho = 4 cm
so = 5 cm
f = 10 cm

1/f = 1/so + 1/si
1/10 = 1/5 + 1/si
1/10 - 1/5 = 1/si
1/10 - 2/10 = 1/si
-1/10 = 1/si
si = -10cm

|si/so| = hi/ho
10/5 = hi/4
5hi = 40
hi = 40/5
hi = 8 cm (b)