Which two main considerations arekept in mind while designing the objective of an astronomical telescope?

You are given the following three lenses. Which two lenses will you use as an eye piece and as an objective to construct an astronomical telescope? Give reasons.

Two convex lenses of same focal length but of aperture D_1 and D_2(D2 lt D1) ,are used as the objective lenses in two astronomical telescopes having identical eyepieces. what is the ratio of their resolving powers? Which telescope will you prefer and why ? Give reason.

Explain, with the help of a schematic diagram, the principle and working of a Light Emiting Diode. What criterion is kept in mind while choosing the semiconductor material for such a device ? Write any two advantages of light emiting diode over conventional incandescent lamps.

What are the two main objects of biological classification?

Astronomers prefer to use telescopes with large objective diameters to observe astronomical objects. why?

A telescope is used to resolve two stars separated by 4.6 xx 10^(-6) radian.If the wavelength fo light used is 5,460 overset @A ,what shold be the aperture of the objective of the telescope?

The magnifying power an astronomical telescope in the normal adjustment position is 100. The distance between the objective and the eyepiece is 101 cm. calculate the focal length of the objective and the eyepiece.

What do you understand by elevation and angular distance between two stars ? How does angular measurement help us to determine. Size of astronomical objects and distances.