EASY
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What is the reflecting telescope used for?

Important Questions on Observing Space : Telescopes

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In normal adjustment, for a refracting telescope, the distance between objective and eye piece is 30 cm. The focal length of the objective, when the angular magnification of the telescope is 2, will be:
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Explain the reflective telescope with diagram and write its advantages over refractive telescope. On what factors does its resolving power depend?
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The ratio of resolving power of telescope, when lights of wavelengths 5000 A and 4000 A are used, is _____
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The focal lengths of objective lens and eye lens of a Galilean Telescope are respectively 30 cm and 3.0 cm. Telescope produces virtual, erect image of an object situated far away from it at least distance of distinct vision from the eye lens. In this condition the Magnifying Power of the Galilean Telescope should be :

MEDIUM
The magnifying power of a telescope with tube length 60cm is 5. What is the focal length of its eye piece?
MEDIUM
A telescope has an objective lens of focal length 150 cm and an eyepiece of focal length 5 cm. If a 50 m tall tower at a distance of 1 km is observed through this telescope in a normal setting, the angle formed by the image of the tower is θ, then θ is close to
EASY
Draw a neat labelled ray diagram of a reflecting telescope of any type.
MEDIUM
In a compound microscope, the magnified virtual image is formed at a distance of 25 cm from the eye-piece. The focal length of its objective lens is 1 cm. If the magnification is 100 and the tube length of the microscope is 20 cm, then the focal length of the eye-piece lens (in cm) is ______
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Why do prefer an objective of large aperture in a telescope?
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What is Presbyopia? Describe the construction and working of reflecting telescope. Draw necessary ray diagram.
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An observer looks at a distant tree of height 10 m with a telescope of magnifying power of 20. To the observer, the tree appears as
MEDIUM

In an astronomical telescope of refracting type:

MEDIUM
It the focal length of objective lens is increased then magnifying power of:
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In an astronomical telescope in normal adjustment a straight black line of the length L is drawn on inside part of objective lens. The eye-piece forms a real image of this line. The length of this image is l . The magnification of the telescope is:
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If we need a magnification of 375 from a compound microscope of tube length 150mm and an objective of focal length 5mm, the focal length of the eye-piece, should be close to:
EASY
What is the magnifying power of a simple microscope of focal length 5 cm, if the image is formed at the distance of distinct vision?
MEDIUM
Draw a ray diagram to sow image formation in a compound microscope. Define its magnifying power and write relation for it.
EASY
Discuss the difference between a refracting telescope and reflecting telescope by giving three points.
EASY
You are given two convex lenses of focal lengths 10 cm and 60 cm. To make a telescope, which of the two lenses will you use as object lens and which one as eye lens?
HARD
A astronomical telescope has objective and eyepiece of focal lengths 40 cm and 4 cm respectively. To view an object 200 cm away from the objective, the lenses must be separated by a distance: