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प्रश्न
State whether concave lens has a real focus or a virtual focus.
उत्तर
A concave lens has a virtual focus because the light rays do not actually pass through the focus.
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संबंधित प्रश्न
List some things that concave lens and concave mirror have in common.
An object 2 cm tall stands on the principal axis of a converging lens of focal length 8 cm. Find the position, nature and size of the image formed if the object is:
(i) 12 cm from the lens
(ii) 6 cm from the lens
State one practical application each of the use of such a lens with the object in position (i) and (ii).
If the image formed by a lens is always diminished and erect, what is the nature of the lens?
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.
A concave lens of focal length 15 cm forms an image 10 cm from the lens. How far is the object placed from the lens? Draw the ray diagram.
An object 60 cm from a lens gives a virtual image at a distance of 20 cm in front of the lens. What is the focal length of the lens? Is the lens converging or diverging? Give reasons for your answer.
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.State three characteristics of the image.
Give two characteristic of the image formed by a concave lens.
Define the principal focus of a concave lens.
Define the term principal foci as applied to a concave lens. Illustrate your answer with the aid of proper diagrams. Show the focal length of the lens in the diagram.
