Optics Question 659
Question: The combination of a convex lens (f = 18 cm) and a thin concave lens (f = 9 cm) is
[AMU (Engg.) 2001]
Options:
A) A concave lens (f = 18 cm)
B) A convex lens (f = 18 cm)
C) A convex lens (f = 6 cm)
D) A concave lens (f = 6 cm)
Show Answer
Answer:
Correct Answer: A
Solution:
$ \frac{1}{F}=\frac{1}{+18}+\frac{1}{(-9)}\Rightarrow F=-18 $ cm (i.e. concave lens)
