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प्रश्न
Things always look small on viewing through a lens. What is the nature of the lens?
उत्तर
It is a concave lens because only a concave lens forms a diminished image at all times.
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संबंधित प्रश्न
If an object is placed 21 cm from a converging lens, the image formed is slightly smaller than the object. If the object is placed 19 cm from the lens, the image formed is slightly larger than object. The approximate focal length of the lens is ______.
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.
Which type of lens is
a diverging lens? Explain your answer with diagrams.
An object is placed at a distance of 4 cm from a concave lens of focal length 12 cm. Fine the position and nature of the image.
Only one of the following applies to a concave lens. This is:
(a) focal length is positive
(b) image distance can be positive or negative
(c) height of image can be positive or negative
(d) image distance is always negative
The power of a converging lens is 4.5 D and that of a diverging lens is 3 D. The power of this combination of lenses placed close together is :
(a) +1.5D
(b) +7.5D
(c) −7.5D
(d) −1.5D
Study the diagram below.
- Name the lens LL’.
- What are the points O and O' called ?
- Complete the diagram to form the image of the object AB.
- State three characteristics of the image.
If the image formed by a lens is diminished in size and erect, for all positions of the object, what type of lens is it?
Draw images in case of a concave lens when the object is at any point on the principal axis between the lens and infinity.
Identify the device used as a spherical mirror or lens in following case, when the image formed is virtual and erect in case.
Object is placed between infinity and device, image formed is diminished and between focus and optical centre on the same side as that of the object.
