Telescope
ÇA compound microscope must posses
high power of gathering lightPe
(i)
large field of view
(i)
high resolving power, and
correction for aberrations:
(iv)
TELESCOPE:: GIve construction and working of an astronomical telesu
an expression for its magnifying power.
Ans. elescope is an optical instrument used to make distant objects appear
sO that they may be seen distinctly. An astronomical telescop
heavenly bodies (e.g. planets, moons, stars, etc.)
Principle
A telescope apparently increases the visual angle. The image of a distant ooj
smaller but it looks large through a telescope because it is much nearer to the eye a
a large Visual angle.
Construction: An astronomical telescope consists of a tube with a lens at eaci
end. It comprises two convex lenses.
(1) Objective
c Coverging lens towards the obiect is called "objective". It has lone
length and large aperture.514 Chopter -10
COLLEGE PHYSICS
First Year
3)
focal length of objective
Angular magnification focal length of eye-piece
of in
Conclusion:
For high magnification, the focal length of the objective should be very 1arge
Moreover, the aperture of the object should be large to increase the brightness ot the
image.
Features:
A telescope must possess
(1)
high power of gathering light.
(2)
large filed of view.
(3)
high resolving power
(4)
cross-wires in eye the piece for measurement/ focussing.
(5)
TERRESTRIAL TELESECOPE:
correction for aberrations.
We
Describe construction
and working of a terrestrial telescope.
Jerive an expression for its magnification.
Th
are
: Definition:A terrestrial telescope is an optical instrument used to view distant objects on the earth clearly A telescope apparently increases the visual angle. The image of a distant object is
smaller, but it looks larger through a telescope because it is much near to the eye and hasa larger visual angle
CONSTRUCTION:A terrestrial telescope consists of three convex lenses
Obiective The converging lens kept towards the object is called objective. It has longer focal
length .
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