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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.
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
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संबंधित प्रश्न
A magnifying glass forms ______.
Ray diagram for the formation of image by a magnifying glass.
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Name the lens used as a magnifying glass.
Name the lens for which magnification can be 1. For what position of the object will the magnification be 1?
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.
What is a magnifying glass (or a simple microscope)? Draw a ray diagram to show how a convex lens may be used as a magnifying glass. Where should the object be placed? State three characteristics of the image formed.
(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?
State two uses of magnifying glass.
