Optics Question 374
Question: An achromatic telescope objective is to be made by combining the lenses of flint and crown glasses. This proper choice is
[CPMT 1977]
Options:
A) Convergent of crown and divergent of flint
B) Divergent of crown and convergent of flint
C) Both divergent
D) Both convergent
Show Answer
Answer:
Correct Answer: A
Solution:
For achromatic telescope objective lens, convergent of crown and divergent of flint is the best combination because $ {\mu _{crown}}<{\mu _{flint}} $
