If an astronomical telescope has objective and eye-piece focal lengths of $200 \; cm$ and $4 \; cm$ respectively,then the magnifying power of the telescope for normal vision is:

If both the object and the image are at infinite distances from a refracting telescope,its magnifying power will be equal to:

$A$ small telescope has an objective lens of focal length $140 \ cm$ and an eyepiece of focal length $5 \ cm$. The magnifying power of the telescope for viewing a distant object when the telescope is in normal adjustment is . . . . . . .

The magnifying power of a refracting type of astronomical telescope is $m$. If the focal length of the eyepiece is doubled,then the magnifying power will become:

$A$ reflecting telescope has a large mirror as its objective with a radius of curvature equal to $80 \, cm$. What is the magnifying power of this telescope if the eyepiece used has a focal length of $1.6 \, cm$?

The diameter of the moon is $3.5 \times 10^3 \text{ km}$ and its distance from the earth is $3.8 \times 10^5 \text{ km}$. If it is seen through a telescope whose focal lengths for the objective and eye lens are $4 \text{ m}$ and $10 \text{ cm}$ respectively,then the angle subtended by the moon on the eye will be approximately.......$^o$