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:

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

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.......$^o$

The diameter of the moon is $3.5 \times 10^{3} \, km$ and its distance from the Earth is $3.8 \times 10^{5} \, km$. It is viewed by a telescope with objective and eyepiece focal lengths of $4 \, m$ and $10 \, cm$ respectively. What is the angular diameter of the image of the moon in degrees?

$A$ Galileo telescope has an objective of focal length $100 \, cm$ and magnifying power $50$. The distance between the two lenses in normal adjustment will be....$cm$

An astronomical telescope has an eyepiece of focal length $5 \ cm$. The angular magnification in normal adjustment is $10$. When the final image is formed at the least distance of distinct vision $(25 \ cm)$ from the eyepiece,then the angular magnification will be: