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प्रश्न
With the help of a diagram, explain why the image of an object viewed through a concave lens appears smaller and closer than the object.
उत्तर
If we place an object anywhere between optical center and infinity, then the refraction occurs as in the below diagram:
It is clear in the above ray diagram that the refracted rays meet a point within the focus. And also, this image virtual,erect and smaller than the object.
Thus, if an object is viewed through a concave lens, its image is appeared smaller and closer than the object.
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संबंधित प्रश्न
If the numerical value of the power of this lens is 10 D, what is its focal length in the Cartesian system ?
An object lies at a distance of 2f from a concave lens of focal length f. Draw a ray-diagram to illustrate the image formation.
(a) Find the position and size of the virtual image formed when an object 2 cm tall is placed 20 cm from:
(i) a diverging lens of focal length 40 cm.
(ii) a converging lens of focal length 40 cm.
(b) Draw labelled ray diagrams to show the formation of images in case (i) and (ii) above (The diagrams may not be according to scale).
An object is placed on the axis of a lens. An image is formed by refraction in the lens. For all positions of the object on the axis of the lens, the positions of the image are always always between the lens and the object name the lens.
- Name the lens which always forms an erect and virtual image.
- State whether the image in part (a) is magnified or diminished.
An object is placed at a distance 24 cm in front of a convex lens of focal length 8 cm.
(i) What is the nature of the image so formed?
(ii) Calculate the distance of the image from the lens.
(iii) Calculate the magnification of the image.
State three characteristics of the image of an extended source, formed by a concave lens.
Define the principal focus of a concave lens.
Draw images in case of a concave lens when the object is at any point on the principal axis between the lens and infinity.
Distinguish between Concave lens and Convex Lens.
