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प्रश्न
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.
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उत्तर
Object distance, u = -20 cm
Focal length, f = -20 cm (concave lens)
For a lens, magnification is
m = `"v"/"u"`
`therefore "m" = (-10)/-20`
∴ m = + 0.5
संबंधित प्रश्न
The following diagram shows an object AB and a converging lens L with foci F1 and F2 State three characteristics of the image in relation to the object.
Ray diagram for the formation of image by a magnifying glass.
What are conjugate foci?
Define the term magnifying power of a simple microscope. How does it depend on the focal length of the lens used?
Will the image formed by a magnifying glass be real or virtual?
Name the lens for which magnification is always less than 1.
How is the magnification (m) produced by a lens related to the object distance (u) and the image distance (v)?
An object is placed in front of a lens between its optical centre and the focus and forms a virtual, erect, and diminished image. Draw a ray diagram to show the formation of the image with the above-stated characteristics.
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?
