Advertisements
Advertisements
प्रश्न
Explain the basic differences between the construction and working of a telescope and a microscope
उत्तर
| Telescope | Microscope |
| It is used for observing distant images of heavenly bodies such as stars and planets. |
It is used for observing magnifying |
| The objective lens has a large focal length and large aperture |
The objective lens has a small focal length and short aperture. |
| The eye lens used has small focal length and small aperture. | The eye lens used has moderate focal length and large aperture. |
| The distance between the objective lens and eye lens is adjusted to focus the object situated at infinity. | The objective and eye lens are kept at a fixed distance apart, whereas the distance of the objective lens from the object is adjusted to focus an object. |
APPEARS IN
संबंधित प्रश्न
You are given the following three lenses. Which two lenses will you use as an eyepiece and as an objective to construct a compound microscope?
| Lenses | Power (D) | Aperture (cm) |
| L1 | 3 | 8 |
| L2 | 6 | 1 |
| L3 | 10 | 1 |
Define resolving power of a microscope and write one factor on which it depends
How can the resolving power of a compound microscope be increased? Use relevant formula to support your answer.
Draw a ray diagram to show the working of a compound microscope. Deduce an expression for the total magnification when the final image is formed at the near point.
In a compound microscope, an object is placed at a distance of 1.5 cm from the objective of focal length 1.25 cm. If the eye piece has a focal length of 5 cm and the final image is formed at the near point, estimate the magnifying power of the microscope.
Draw the labelled ray diagram for the formation of image by a compound microscope.
Derive the expression for the total magnification of a compound microscope. Explain why both the objective and the eyepiece of a compound microscope must have short focal lengths.
A compound microscope forms an inverted image of an object. In which of the following cases it it likely to create difficulties?
compound microscope consists of two convex lenses of focal length 2 cm and 5 cm. When an object is kept at a distance of 2.1 cm from the objective, a virtual and magnified image is fonned 25 cm from the eye piece. Calculate the magnifying power of the microscope.
A microscope is focussed on a mark on a piece of paper and then a slab of glass of thickness 3 cm and refractive index 1.5 is placed over the mark. How should the microscope be moved to get the mark in focus again?
The near vision of an average person is 25 cm. To view an object with an angular magnification of 10, what should be the power of the microscope?
| 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:
