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प्रश्न
Give the position, size and nature of image of formed by a concave lens when the object is placed:
at infinity.
उत्तर
In the case of a concave lens, when an object is placed at infinity, the image is formed at the focus. The image formed is virtual, erect and highly diminished.
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संबंधित प्रश्न
Due to gradual weakening of ciliary muscles and diminishing flexibility of the eye lens a certain defect of vision arises. Write the name of this defect. Name the type of lens required by such persons to improve the vision. Explain the structure and function of such a lens.
If an object is placed 21 cm from a converging lens, the image formed is slightly smaller than the object. If the object is placed 19 cm from the lens, the image formed is slightly larger than object. The approximate focal length of the lens is ______.
Fill in the following blank with suitable word:
A convex lens .................. rays of light, whereas a concave lens .................. rays of light.
An object is placed 10 cm from a lens of focal length 5 cm. Draw the ray diagrams to show the formation of image if the lens is converging,
The power of a concave lens is 10 D and that of a convex lens is 6 D. When these two lenses are placed in contact with each other, the power of their combination will be :
(a) +16 D
(b) +4 D
(c) −16 D
(d) −4 D
A lens forms an upright and diminished image of an object irrespective of its position. What kind of lens is this?
A concave lens, if kept at a proper distance from an object, can form its real image.
The diagrams showing the correct path of the ray after passing through the lens are:
 |
 |
| I | II |
 |
 |
| III | IV |
Distinguish between concave and convex lens.
