NEET Solved Paper 2018 Question 10
Question: An astronomical refracting telescope will have large angular magnification and high angular resolution, when it has an objective lens of [NEET - 2018]
Options:
A) Large focal length and large diameter
B) Large focal length and small diameter
C) Small focal length and large diameter
D) Small focal length and small diameter
Show Answer
Answer:
Correct Answer: A
Solution:
For telescope, angular magnification $ \text{=}\frac{{f_0}}{{f_E}} $
So, focal length of objective lens should be large.
Angular resolution $ =\frac{D}{1.22\lambda } $ should be large.
So, objective should have large focal length $ (f _0) $ and large diameter D.
