JEE · NEET Previous Year Question
A lens of large focal length and large aperture is best suited as an objective of an astronomical telescope, since [NEET 2021]
Topic: NEET PYQ
Answer: D. Full step-by-step solution below.
- Aa large aperture contributes to the quality and visibility of the images
- Ba large area of the objective ensures better light gathering power
- Ca large aperture provides a better resolution
- DAll of the above
Correct answer: D
Solution
(d) The objective of an astronomical telescope has large focal length and large aperture. Because the lens used is a convex lens, the magnification of an astronomical telescope is directly proportional to the focal length of the objective lens.This large aperture also contributes to the better quality and visibility of the images. Thus, it provides better resolution.
Due to large focal length of the objective, it covers large area which ensures better light gathering power.
Thus, all options (a), (b) and (c) are correct.
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