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Q61 (NDA-I/2010) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Geometrical optics Answer Verified

The ratio of the focal length of the objective to the focal length of the eyepiece is greater than one for

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Your answer: —  Â·  Correct: B
Explanation

In optical instruments, the ratio of the focal length of the objective ($f_o$) to the focal length of the eyepiece ($f_e$) determines the angular magnification. For a telescope, the magnification is given by $M = f_o / f_e$. To achieve high magnification of distant objects, telescopes are designed with a long focal length objective and a short focal length eyepiece, making the ratio $f_o / f_e > 1$. For example, a telescope might have a 1500mm objective and a 25mm eyepiece. Conversely, in a compound microscope, the objective has a very short focal length to produce a high linear magnification of a nearby object, while the eyepiece has a relatively larger focal length to further magnify that image. Therefore, in a microscope, the ratio $f_o / f_e$ is typically less than one, whereas for a telescope, it is greater than one.

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SIMILAR QUESTIONS

NDA-I · 2008 · Q3 Relevance score: 6.42

Consider the following statements : 1. The focal length of the objective of a microscope is less than the focal length of the eyepiece. 2. The minimum distance between an object and its real image formed by a convex lens of focal length f is equal to 4 f. Which of the statements given above is/are correct?

NDA-II · 2018 · Q44 Relevance score: 5.74

Consider the following statements about a microscope and a telescope : 1. Both the eyepiece and the objective of a microscope are convex lenses. 2. The focal length of the objective of a telescope is larger than the focal length of its eyepiece 3. The magnification of a telescope increases with the increase in focal length of its objective. Which of the statements given above are correct?

NDA-I · 2019 · Q49 Relevance score: 5.18

The focal length of the objective lens of a telescope is 50 cm. If the magnification of the telescope is 25, then the focal length of the eye-piece is

NDA-II · 2015 · Q16 Relevance score: 4.90

In case of a compound microscope which of the following statements is / are correct? 1. The focal length of the eye piece is larger than the focal length of the objective 2. The focal length of the eye piece is smaller than the focal length of the objective 3. The image produced in a normal optical microscope is real 4. The image produced in a normal optical microscope is virtual Select the correct answer using the code given below:

CAPF · 2018 · Q2 Relevance score: 3.51

Which of the following statements about optical microscope is/are correct? 1. Both the eyepiece and objective of a microscope are convex lenses. 2. The magnification of a microscope increases with increase in focal length of the objective. 3. The magnification of a microscope depends upon the length of the microscope tube, 4. The eyepiece of a microscope is a concave lens. Select the correct answer using the code given below.