To produce a magnified erect image of a far object,along with a convex lens,we will require:

On which of the following does the magnifying power of a telescope depend?

In an astronomical telescope,the focal lengths of the objective lens and the eyepiece are $150 \, cm$ and $6 \, cm$ respectively. In the case where the final image is formed at the least distance of distinct vision,the magnifying power is:

An astronomical telescope has objective and eye-piece lenses of powers $0.5\, D$ and $20\, D$ respectively. Its magnifying power will be:

In normal adjustment,for a refracting telescope,the distance between the objective and the eyepiece is $30\,cm$. The focal length of the objective,when the angular magnification of the telescope is $2$,will be $.....\,cm$.

The focal lengths of the lenses of an astronomical telescope are $50\, cm$ and $5\, cm$. The length of the telescope when the image is formed at the least distance of distinct vision is