SATHEE: ray-optics-and-optical-instruments Question 44

Ray Optics And Optical Instruments

ray-optics-and-optical-instruments Question 44

Question: Q. 2. (i) Draw a labelled ray diagram of an astronomical telescope to show the image formation of a distant object. Write the main considerations required in selecting the objective and eyepiece lenses in order to have large magnifying power and high resolution of the telescope.

(ii) A compound microscope has an objective of focal length $1.25 cm$ and eyepiece of focal length $5 cm$ . A small object is kept at $2.5 cm$ from the objective. If the final image formed is at infinity, find the distance between the objective and the eyepiece.

U] [Foreign 2014]

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Solution:

Ans. (i) Try yourself, Similar to Q. 1, Short Answer Type Questions-II

Alternatively,

For a large magnifying power, $f_{o}$ should be large and $f_{e}$ should be small.

For a higher resolution, the diameter of the objective should be large.

$\begin{aligned} (ii) & \frac{1}{v_{0}} - \frac{1}{u_{0}} = \frac{1}{f_{0}} & \frac{1}{v_{0}} = \frac{1}{f_{0}} + \frac{1}{u_{0}} = \frac{1}{1.25} - \frac{1}{2.5} = \frac{1}{- 2.5} & v_{o} = - 2.5 cm & L = | f_{0} | + | f_{e} | & = (2.5 + 5.0) cm = 7.5 cm 1 / 2 & 1 / 2 \end{aligned}$

[Note for students : You may draw refractive or reflective telescope].

[CBSE Marking Scheme 2014]

Ray Optics And Optical Instruments

ray-optics-and-optical-instruments Question 44

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Ray Optics And Optical Instruments

ray-optics-and-optical-instruments Question 44

Table of Contents

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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