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Question
Draw a labeled ray diagram of a reflecting telescope. Mention its two advantages over the refracting telescope.
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Solution
Reflecting Telescope,
Its two advantages over Refracting telescope:
1. It reduces the spherical aberration and forms a clear focused image.
2. It doesn’t require a lens of very large aperture as refracting type requires that cannot be manufactured easily.
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| 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. |
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OR
Write two distinct advantages of a reflecting type telescope over a refracting type telescope.
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| There are two types of optical instruments: Microscopes and Telescopes. Microscopes are used to magnify very tiny objects whereas telescopes are used to study distant objects. Both of them deploy convex lenses. In his telescope, Newton used a large parabolic mirror to collect light from the stars and reduce aberrations. |
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-
What is the difference between a compound microscope and an astronomical telescope (refracting type), as far as their lenses are concerned?
Useful Constants & Relations:
| 1 | Charge of a proton | e | 1.6 × 10-19 C |
| 2 | Speed of light in vacuum | c | 3 × 108 ms-1 |
| 1 u = 931 MeV | |||
