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प्रश्न
How will you differentiate between a convex and a concave lens by looking at a distant object.
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उत्तर
On seeing a distant object through the lens, if its inverted image is seen, then the lens is convex, and if the upright image is seen, then the lens is concave.
संबंधित प्रश्न
In figure, (a) and (b), F1 and F2 are the two foci of thin lenses and AB is the incident ray. Complete the diagram to show the path of the ray AB after refraction through each lens.
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| (a) |
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| (b) |
A ray of light incident on a lens parallel to its principal axis, after refraction passes through or appears to come from ______.
Study the diagram shown in Fig. 5.56
Where is the image formed?

A ray of light incident parallel to the principal axis of a lens, passes undeviated after refraction.
A ray of light incident at the optical centre of lens, passes undeviated after refraction.
What type of lenses are used in spectacles worn by an old lady for knitting?
In the following diagram ., the object and the image formed by the respective lenses are shown. Complete the ray diagram, and locate the focus. Find the focal length of the lens.

In the following diagram the object and the image formed by the respective lenses are shown. Complete the ray diagram, and locate the focus. Find the focal length of the lens.

State the nature and position of the object on the principal axis to obtain a real and magnified image.
When does a ray of light falling on a lens pass through it undeviated?


