Bayangan sebuah lilin berasa pada jarak 50cm dibelakang lensa cembung. apabila jarak benda ke lensa 200 cm, hitunglah a. jari - jari lensa b. kekuatan lensa
tribeking22
A. 1/s + 1/s' = 1/f 1/200 + 1/50 = 1/f 1/200 + 4/200 = 1/f 5/200 = 1/f 5f = 200 f = 200:5 f = 40 cm
1/200 + 1/50 = 1/f
1/200 + 4/200 = 1/f
5/200 = 1/f
5f = 200
f = 200:5
f = 40 cm
R = 2f
R = 2×40
R = 80 cm
b. P = 100/f
P = 100/40
P = +2,5 D