Question

Sebuah benda diletakkan 20cm di depan cermin cekung yg jari" kelengkungan 30cm jika tinggi benda 4cm hitunglah:
a.jarak fokus
b. jarak bayangan
c. pembesar bayangan
d. tinggi bayangan

Answer 1

A.f = 1/2 r
f= 1/2. 30
f= 15

b. 1/si = 1/f - 1/so
1/si = 1/15 - 1/20
1/si = 4/60 -3/60
si = 60

c. M= si/so = 60 /20 = 3

d. hi = M.ho = 3 x4 = 12cm

Answer 2

Diket:
s = 20cm
R = 30cm
h = 4cm
Ditanya:
a . Jarak fokus (f)
b. Jarak bayangan (s')
c. Perbesaran (M)
d. Tinggi bayangan (h')
Jawab:
a). f = 1/2 R
f = 1/2 30cm
f = 15cm
b) 1/s' = 1/f - 1/s
1/s' = 1/15 - 1/20
1/s' = 4/60 - 3/60
1/s' = 1/60
s' = 60cm
c).I M = s'/s I
M = 60/20
M = 3 kali
d. M = h'/h
3 = h'/4
h' = 12cm