$A$ small telescope has an objective of focal length $140 \ cm$ and an eyepiece of focal length $5.0 \ cm$. The magnifying power of the telescope for viewing a distant object is:

The focal length of the objective and the eyepiece of a telescope are $50\,cm$ and $5\,cm$ respectively. If the telescope is focused for distinct vision on a scale distant $2\,m$ from its objective,then its magnifying power will be

What is the angular magnification of a telescope if the focal lengths of the objective and eye lenses are $10 \ cm$ and $10 \ mm$ respectively,and the tube length is $11 \ cm$?

The magnifying power of a telescope with tube length $60 \; cm$ is $5$. What is the focal length of its eyepiece in $cm$?

An astronomical refracting telescope has an objective of focal length $20 \, m$ and an eyepiece of focal length $2 \, cm$. Then:

An astronomical telescope has an objective and an eyepiece of focal lengths $40\, cm$ and $4\, cm$ respectively. To view an object $200\, cm$ away from the objective,the lenses must be separated by a distance of.....$cm$.