The focal length of the objective of a terrestrial telescope is 80 cm and it is adjusted for normal vision to produce a magnification of 20. If the focal length of erecting lens is 20cm, then full length of telescope tube will be ___
see full answer
Your Exam Success, Personally Taken Care Of
1:1 expert mentors customize learning to your strength and weaknesses – so you score higher in school , IIT JEE and NEET entrance exams.
An Intiative by Sri Chaitanya
a
84cm
b
100cm
c
124 cm
d
164 cm
answer is D.
(Unlock A.I Detailed Solution for FREE)
Best Courses for You
JEE
NEET
Foundation JEE
Foundation NEET
CBSE
Detailed Solution
For normal vision,fofe = m ⇒ 80fe = 20 ⇒ fe = 4cm ∴ L = fo+4f+fe = 80+4×20+4cm = 164cm
The focal length of the objective of a terrestrial telescope is 80 cm and it is adjusted for normal vision to produce a magnification of 20. If the focal length of erecting lens is 20cm, then full length of telescope tube will be ___