A galilien telescope is 27 cm long when focused to form an image is at infinity.If the focal length of obdject has a focal length of 30cm ,What is the focal length of eyepiece.
suryansh , 11 Years ago
Grade 12
2 Answers
Saurabh Koranglekar
Last Activity: 4 Years ago
Focal length of the objective, fo = 30 cm
Length of the tube, L = 27 cm
Now,
L = fo-fe
In a Galilean telescope, the eyepiece lens is concave.
Thus, we have:
fe = fo – L = 30 – 27 = 3 cm
Vikas TU
Last Activity: 4 Years ago
For the given Galilean telescope,
(When the image is formed at infinity)
F base 0 = 30 cm,
L = 27 cm
Since L = f base 0 – |f base e| [Since, concave eyepiece lens is used in Galilean Telescope] ⇒ f base e
= f base 0 – L
= 30 – 27
= 3
Provide a better Answer & Earn Cool Goodies
LIVE ONLINE CLASSES
Prepraring for the competition made easy just by live online class.
Full Live Access
Study Material
Live Doubts Solving
Daily Class Assignments
Ask a Doubt
Get your questions answered by the expert for free
Other Related Questions on engineering entrance exams