NCERT Class XII Chapter
Ray Optics and Optical Instruments
Questions With Solutions
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Question : 34
Total: 38
A small telescope has an objective lens of focal length 140 cm and an eyepiece of focal length 5.0 cm. What is the magnifying power of the telescope for viewing distant objects when:
(a) the telescope is in normal adjustment (i.e., when the final image is at infinity)?
(b) the final image is formed at the least distance of distinct vision (25 cm)?
(a) the telescope is in normal adjustment (i.e., when the final image is at infinity)?
(b) the final image is formed at the least distance of distinct vision (25 cm)?
Solution:
(a) In normal adjustment magnifying power
m =−
(b) For the image at least distance of distinct vision
Magnifying power m =
[ 1 +
] [
]
m =
(b) For the image at least distance of distinct vision
Magnifying power m =
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