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प्रश्न
| A compound microscope consists of two converging lenses. One of them, of smaller aperture and smaller focal length, is called objective and the other of slightly larger aperture and slightly larger focal length is called eye-piece. Both lenses are fitted in a tube with an arrangement to vary the distance between them. A tiny object is placed in front of the objective at a distance slightly greater than its focal length. The objective produces the image of the object which acts as an object for the eye-piece. The eye-piece, in turn, produces the final magnified image. |
The focal lengths of the objective and eye-piece of a compound microscope are 1.2 cm and 3.0 cm respectively. The object is placed at a distance of 1.25 cm from the objective. If the final image is formed at infinity, the magnifying power of the microscope would be:
पर्याय
100
150
200
250
उत्तर
200
Explanation:
Applying the lens formula for the objective lens,
`1/"v"_0 - 1/"u"_0 = 1/"f"_0`
Or, `1/"v"_0 + 1/1.25 = 1/1.2`
∴ v0 = 30 cm
Magnification = `"v"_0/"u"_0 "D"/"f"_"e"`
= `30/1.25 xx 25/3`
= 200
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संबंधित प्रश्न
Explain the basic differences between the construction and working of a telescope and a microscope
A compound microscope consists of an objective lens of focal length 2.0 cm and an eyepiece of focal length 6.25 cm separated by a distance of 15 cm. How far from the objective should an object be placed in order to obtain the final image at
- the least distance of distinct vision (25 cm), and
- infinity?
What is the magnifying power of the microscope in each case?
How can the resolving power of a compound microscope be increased? Use relevant formula to support your answer.
Draw a ray diagram showing the image formation by a compound microscope. Hence obtained expression for total magnification when the image is formed at infinity.
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(a) Simple microscope
(b) Compound microscope
(c) Astronomical telescope
(d) Galilean telescope
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An angular magnification of 30X is desired using an objective of focal length 1.25 cm and an eye piece of focal length 5 cm. How will you set up the compound microscope for the final image formed at least distance of distinct vision?
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