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प्रश्न
How could you find the focal length of a convex lens rapidly but approximately?
उत्तर
To determine the focal length of a convex lens, place the convex lens in a holder and keep it in front of a distant object like a tree. A cardboard screen is put behind the lens. Now, change the distance of the screen from the convex lens until a clear, inverted image of the tree is formed on the screen. Measure the distance of the screen from the lens. This distance will be the focal length of the convex lens. Here, we have used the fact that the image of an object at a far distance is formed at the focus of a convex lens.
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संबंधित प्रश्न
Which of the following lenses would you prefer to use while reading small letters found in a dictionary?
Describe with the help of a ray-diagram, the formation of image of a finite object placed in front of convex lens between f and 2f. Give two characteristics of the image so formed.
A convex lens of focal length 6 cm is held 4 cm from a newspaper which has print 0.5 cm high. By calculation, determine the size and nature of the image produced.
What kind of lens can form:
an inverted diminished image?
Which part causes the greatest convergence?
For finding the focal length of a convex lens by obtaining the image of a distant object, one should use as the object.
(1) a well lit distant tree
(2) window grill in the class room
(3) any distant tree
(4) a lighted candle kept at the other end of the table.
Where should an object be placed in front of a convex lens to get a real image of the size of the object?
State the position of object, position of image, nature of image when: Convex lens is used as objective lens of photographic camera.
Object at 2F1 of a convex lens : Image at 2F2 : : Object at F1 : _______
A convex lens of focal length 20 cm can produce a magnified virtual as well as real image. Is this a correct statement? If yes, where shall the object be placed in each case for obtaining these images?
