Discussion Forum



1)

Two lens of focal length f1= 10 cm and f2= -20 cm are kept as shown. The resultant power of combination will be

1752021608_p6.JPG


A) -10 D

B) 5 D

C) 0

D) 10 D

Answer:

Option D

Explanation:

$P= 2\left[\frac{100}{10}+\frac{100}{-20}+0\right]$

 P= 10 dipotre