What is a telescope?

The focal length of the objective and eyepiece of a telescope are respectively $200 \, cm$ and $5 \, cm$. The maximum magnifying power of the telescope will be

The aperture of a telescope is made large,because

The length of a telescope is $36 \ cm$. The focal lengths of its lenses can be

The objective lens of a telescope has a focal length of $100 \, cm$. When the final image is formed at the least distance of distinct vision,the distance between the lenses is $105 \, cm$. Calculate the focal length of the eyepiece in $cm$.

If the tube length of an astronomical telescope is $105 \, cm$ and the magnifying power is $20$ for normal setting,calculate the focal length of the objective in $cm$.