Ray Optics Test...

A simple magnifying lens is used in such a way that an image is formed at 25 cm away from the eye. In order to have 10 times magnification, the focal length of the lens should be

A telescope of diameter 2m uses light of wavelength 5000 Å for viewing stars. The minimum angular separation between two stars whose image is just resolved by this telescope is

In Gallilean telescope, if the powers of an objective and eye lens are respectively +1.25 D and –20 D, then for relaxed vision, the length and magnification will be

The aperture of a telescope is made large, because

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

To increase both the resolving power and magnifyingpower of a telescope

A telescope has an objective of focal length 50 cm and an eye piece of focal length 5 cm. The least distance of distinct vision is 25 cm. The telescope is focused for distinct vision on a scale 200 cm away. The separation between the objective and the eye-piece is

A opera glass (Gallilean telescope) measure 9 cm from the objective to the eyepiece. The focal length of the objective is 15 cm. Its magnifying power is

The aperture of the objective lens of a telescope ismade large so as to

On which of the following does the magnifying power of a telescope depends