For a telescope in normal adjustment,the length of the telescope is found to be $27 \, cm$. If the magnifying power of the telescope at normal adjustment is $8$,the focal lengths of the objective and the eyepiece are respectively:

The focal length of the objective and eyepiece of a telescope are respectively $60 \, cm$ and $10 \, cm$. The magnitude of the magnifying power when the image is formed at infinity is:

The objective and eyepiece of an astronomical telescope are double convex lenses with refractive index $1.5$. When the telescope is adjusted to infinity, the separation between the two lenses is $16 \,cm$. If the space between the lenses is now filled with water and the telescope is again adjusted for infinity, then the present separation between the lenses is: (in $\,cm$)

Four convergent lenses have focal lengths $100 \, cm, 10 \, cm, 4 \, cm$ and $0.3 \, cm$. For a telescope with maximum possible magnification,we choose the lenses of focal length

The magnifying power of an astronomical telescope for normal adjustment is given by:

If a telescope is reversed,i.e.,viewed from the objective side,what happens to the appearance of the object?