$A$ Galileo telescope has an objective of focal length $100\,cm$ and magnifying power $50$. The distance between the two lenses in normal adjustment will be......$cm$

$A$ small telescope has an objective lens of focal length $144\;cm$ and an eyepiece of focal length $6.0\;cm$. What is the magnifying power of the telescope? What is the separation between the objective and the eyepiece?

The focal lengths of the lenses of an astronomical telescope are $50\, cm$ and $5\, cm$. The length of the telescope when the image is formed at the least distance of distinct vision is

$A$ lens of large focal length and large aperture is best suited as an objective of an astronomical telescope since :

In a terrestrial telescope,the focal length of the objective is $90\, cm$,the inverting lens is $5\, cm$,and the eye lens is $6\, cm$. If the final image is formed at $30\, cm$ from the eye lens,calculate the magnification.

$A$ telescope has an eyepiece of focal length $5\, cm$ and an objective lens of focal length $60\, cm$. It is focused on a distant object such that the rays emerge from the eyepiece as parallel rays. Find the angular width of the image in degrees $(^o)$ if the object subtends an angle of $2^o$ at the objective.