Where is the largest telescope in India? What is the diameter of the objective in it?

$A$ simple telescope consisting of an objective of focal length $60\,cm$ and a single eye-lens of focal length $5\,cm$ is focused on a distant object in such a way that parallel rays emerge from the eye-lens. If the object makes an angle of $2^o$ at the objective,the angular width of the image is.....$^o$

If a telescope is reversed,i.e.,viewed from the objective side,what happens to the appearance of the object?

$A$ telescope has an objective lens of focal length $144\, cm$ and an eyepiece of focal length $6\, cm$. Find the magnifying power of the telescope for normal adjustment.

An observer looks at a distant tree of height $10 \ m$ with a telescope of magnifying power of $20$. To the observer,the tree appears:

The focal lengths of the objective lens and the eye lens of a Galilean telescope are $30\, cm$ and $3.0\, cm$ respectively. The telescope produces a virtual,erect image of an object situated far away from it at the least distance of distinct vision from the eye lens. In this condition,the magnifying power of the Galilean telescope should be: