41. Focal length of objective eye piece and inverting lens of a terrestrial telescope are 20 cm, 10 cm and 5 cm
respectively. Length of the tube containing these lenses at normal adjustment is
(1) 30 cm
(2) 35 cm
(3) 50 cm
(4) 40 cm
With explanation plz
Answers
Answered by
16
Given:
The focal length of objective eye piece is Fo= 20 cm
The focal length of the inverting lens is Fe=10 cm
The focal length of the telescope is Fi=5 cm
To find:
The length of the containing these lenses at normal adjustments
Solution:
The formula for it is
L=(Fo+4Fi+Fe)
Putting the above values
L=(10+4×5+20)
L=50 cm
So the length of the tube containing lenses is 50 cm.
The option C is correct.
Answered by
1
Answer:
its simple! refer to the pic here
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