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प्रश्न
How will you differentiate between a convex and a concave lens by looking at a distant object.
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उत्तर
On seeing a distant object through the lens, if its inverted image is seen, then the lens is convex, and if the upright image is seen, then the lens is concave.
संबंधित प्रश्न
What is a lens?
In figure, (a) and (b), F1 and F2 are the two foci of thin lenses and AB is the incident ray. Complete the diagram to show the path of the ray AB after refraction through each lens.
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| (a) |
 |
| (b) |
Study the diagram shown in Fig. 5.56
Where is the image formed?
For an object placed at a distance 20 cm in front of a convex lens, the image is at a distance 20 cm behind the lens. The focal length of the convex lens is ______.
Fig shows an object PQ placed on the principle axis of a lens L. The two foci of the kens are F1 and f2. The image formed by the lens is erect, Virtual and dimnished.
(i) Draw the outline ofthe lens L used and Named it.
(ii) Draw a ray of light starting from Q and passing through O. show the same ray after refraction by the lens.
(iii) Draw another ray from Q Which is incident parallel to the principle axis and show how it emerges after refraction from the lens.
(iv) Locate the final image formed.
In the following diagram ., the object and the image formed by the respective lenses are shown. Complete the ray diagram, and locate the focus. Find the focal length of the lens.
Make the correct choices in the following items:
lf the image can be focused on a screen it must be
How will you differentiate between a convex and a concave lens by looking at a printed page?
Complete the following diagram and state what happens to the ray of light after refraction through the lens.
