Question

Benda terletak sejauh 25 cm di depan lensa dan bersifat maya. Diperbesar 2 kali . berapa besar fokus dan kekuatan lensa?

Answer 1

M = -s'/s
2 = -s'/25
-s' = 2.25
s' = -50 cm

1/s + 1/s' = 1/f
1/25 - 1/50 = 1/f
2/50 - 1/50 = 1/f
1/50 = 1/f
f = 50 cm

P = 100/f
P = 100/50
P = +2 D

Answer 2

M= |s'/s•|
2= s'/25
s'=50

1/f=1/s•+1/s'
=1/25+1/50= 2-1/50
f =50 cm

p= 100/PR = 100/50 = 2 D