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प्रश्न
Do we expect any change in the position, nature, and size of the image
(i) formed by a concave lens,
(ii) with a change in the position of the object?
उत्तर
No, the image formed by a concave lens.
(i) Is always formed between the optical centre and the focus of the lens.
(ii) Is always virtual, erect and diminished in size. This is true for all positions of the object on the principal axis.
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संबंधित प्रश्न
Explain with the help of a diagram, why the concave lens is also called a diverging lens.
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).
State one practical use each of convex mirror, concave mirror, convex lens and concave lens.
When an object is placed 10 cm in front of lens A, the image is real, inverted, magnified and formed at a great distance. When the same object is placed 10 cm in front of lens B, the image formed is real, inverted and same size as the object.
What is the focal length of lens B?
(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).
A person finds difficulty in seeing nearby objects clearly. His vision can be corrected by using spectacles containing:
(a) converging lenses
(b) diverging lenses
(c) prismatic lenses
(d) chromatic lenses
A concave lens, if kept at a proper distance from an object, can form its real image.
A lens forms an image between the object and the lens. Name the lens.
When an object is kept within the focus of a concave mirror, an enlarged image is formed behind the mirror. This image is :
Convex lens : converging : : concave lens : _______
