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प्रश्न
What are conjugate foci?
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उत्तर
Two points lying on the principal axis such that the image of an object kept at such point is formed on the other point, are called conjugate foci.
संबंधित प्रश्न
What information about the nature of image is real or virtual, do you get from the sign of magnification + or -?
An illuminated object lies at a distance 1.0 m from a screen. A convex lens is used to form the image of the object on a screen placed at a distance of 75 cm from the lens. Find:
- the focal length of the lens, and
- the magnification.
An object is placed at a distance of 20 cm in front of a concave lens of focal length 20 cm. find: the magnification of image.
What information we seek by the linear magnification of the image when it is positive or negative?
A convex lens produces on a screen an image twice the size of the object. If the position of image and object be interchanged, what will be the magnification then?
Draw a neat diagram to explain the action of a convergent (convex) lens as a reading glass (or magnifying glass). State the characteristics of the image formed.
What is a simple microscope or a magnifying glass? Draw a ray diagram to show its function.
Copy and complete the following ray diagram.
(i) Draw a ray diagram to show how the lens can be used as a ‘magnifying glass’? State the nature of the lens.
(ii) In what respect does the image in (i) above different from the image formed by a concave lens?
Write an expression for the magnifying power of a simple microscope. How can it be increased?
