fisika optika cuma 1 soal (10 poin)

Lensa cembung
m1 = 2 kali, s = 100 mm
m2 = 5 kali
∆s = __?

m = f / (s - f)
f = ms - mf
f (1 + m) = ms
f = ms / (1 + m)

f = f
m2 s2 / (1 + m2) = m1 s1 / (1 + m1)
5 s2 / (1+5) = 2 • 100 / (1+2)
5 s2 = 2 • 100 • 6/3
5 s2 = 400
s2 = 80 mm ← jwb