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प्रश्न
How is the working of a telescope different from that of a microscope?
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उत्तर
A microscope is used to look into smaller details like structure of cells etc. On the other hand, a telescope is used to see larger objects that are very far away like stars, planets etc.
Telescope mainly focuses on collecting the light into the objective lens, which should thus be large, while the microscope already has a focus and the rest is blurred around it.
There is a big difference is in their magnification factors.
For telescope the angular magnification is given by `M = f_0/f_e`
Where f0 is the focal length of the objective lens and fe is the focal length of the eyepiece. For microscope the angular magnification is given by
`M= 1+D/f_0`When image if formed at distance of least distinct vision
`M= D/f_0`When image is formed at infinity
Where D is the distance of least distinct vision and f0 is the focal length of objective lens. Magnifying power of compound microscope
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संबंधित प्रश्न
- For the telescope is in normal adjustment (i.e., when the final image is at infinity)? what is the separation between the objective lens and the eyepiece?
- If this telescope is used to view a 100 m tall tower 3 km away, what is the height of the image of the tower formed by the objective lens?
- What is the height of the final image of the tower if it is formed at 25 cm?
Draw a ray diagram depicting the formation of the image by an astronomical telescope in normal adjustment.
Draw a labelled ray diagram of an image formed by a refracting telescope with the final image formed at infinity. Derive an expression for its magnifying power with the final image at infinity
Write two important limitations of a refracting telescope over a reflecting-type telescope.
Draw a labeled ray diagram of a reflecting telescope. Mention its two advantages over the refracting telescope.
An astronomical telescope uses two lenses of powers 10 dioptres and 1 dioptre. If the final image of a distant object is formed at infinity, calculate the length of the telescope
Draw a labelled ray diagram showing the formation of an image by a refracting telescope when the final image lies at infinity.
Define the term ‘resolving power of a telescope’.
A small telescope has an objective lens of focal length 140 cm and an eyepiece of focal length 5.0 cm. Find the magnifying power of the telescope for viewing distant objects when
- the telescope is in normal adjustment,
- the final image is formed at the least distance of distinct vision.
Read the following paragraph and answer the questions.
| A number of optical devices and instruments have been designed and developed such as periscope, binoculars, microscopes and telescopes utilising the reflecting and refracting properties of mirrors, lenses and prisms. Most of them are in common use. Our knowledge about the formation of images by the mirrors and lenses is the basic requirement for understanding the working of these devices. |
- Why the image formed at infinity is often considered most suitable for viewing. Explain
- In modern microscopes, multicomponent lenses are used for both the objective and the eyepiece. Why?
- Write two points of difference between a compound microscope and an astronomical telescope
OR
Write two distinct advantages of a reflecting type telescope over a refracting type telescope.
