$A$ giant refracting telescope at an observatory has an objective lens of focal length $15 \, m$. If an eyepiece of focal length $1.0 \, cm$ is used,what is the angular magnification of the telescope?

An observer looks at a tree of height $15 \ m$ with a telescope of magnifying power $10$. To him,the tree appears

On which of the following does the magnifying power of a telescope depend?

In a Galilean telescope,the final image formed is:

An astronomical telescope has an angular magnification of magnitude $5$ for distant objects. The separation between the objective and the eyepiece is $36 \, cm$ and the final image is formed at infinity. The focal length $f_o$ of the objective and the focal length $f_e$ of the eyepiece are:

What are reflecting type of telescopes? Explain the advantages and disadvantages of reflecting telescopes as compared to refracting telescopes.