Question

Sebuah benda diletakkan 10 cm di depan cermin cembung. Jika jari-jari kelengkungan cermin 40 cm, jarak bayangannya adalah...

Answer 1

Diketahui :
s = 10 cm
R = 40 cm

ditanyakan :
s' = ?

jawab :
f = -1/2R = -1/2 x x40 = -20 cm

1/f = 1/s + 1/s'
-1/20 = 1/10 + 1/s'
1/s' = -1/20 - 1/10 = -1/20 - 2/20 = -3/20
s' = -20/3 = -6,67 cm

Answer 2

S = 10 cm
R = -40 cm ; f = -20 cm
1/s' = 1/f - 1/s
1/s' = 1/-20 - 1/10
1/s' = -1/20 - 2/20
1/s' = -3/20
s' = -20/3
s' = -6,6cm