Uji Kompetensi Bab 5, no.6

Diket:

Cermin cekung (A)

R_A=80 cm

f_A=40 cm

Cermin cembung (B)

R_B= -40 cm

f_B= -20cm

d = 100 cm

Dit : S’_B

Jawab :

S_A= ½ x 100=50 cm

1/S_A + 1/S’_A = 1/f_A

1/50 + 1/S’_A = 1/40

1/S’_A = 1/200

S’_A = 200 cm

d = S’_A + S_B

100=200 + S_B

S_B= -100 cm

1/ S_B + 1/S’_B=1/f_B

1/-100 + 1/S’_B=1/-20

S’_B=-25cm di belakang cermin (Jawaban A)

By: Jessica Tjan / XJ - 24