Two convex lenses of focal lengths $0.3 \, m$ and $0.05 \, m$ are used to make a telescope. The distance kept between the two is .... $m$

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:

If the focal length of the objective lens is increased,then:

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

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

Write a note on Cassegrain telescope.