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प्रश्न
Explain optical centre of a lens with the help of proper diagram(s).
उत्तर
Optical centre: "It is the point in the lens on the principal axis such that a ray of light passing through this point emerges parallel to the direction of incidence (or goes undeviated)."
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संबंधित प्रश्न
A ray of light after refraction through a lens emerges parallel to the principal axis of the lens. The incident ray either passes through ______.
Fig shows an object PQ placed on the principle axis of a lens L. The two foci of the kens are F1 and f2. The image formed by the lens is erect, Virtual and dimnished.
(i) Draw the outline ofthe lens L used and Named it.
(ii) Draw a ray of light starting from Q and passing through O. show the same ray after refraction by the lens.
(iii) Draw another ray from Q Which is incident parallel to the principle axis and show how it emerges after refraction from the lens.
(iv) Locate the final image formed.
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.
Make the rrect choices in the following items :
An object is placed 50 cm from a connverging lens of focal length 30 cm. The image produced would be
A lens forms the image of an object placed at a distance of 45 cm from it on a screen placed at a distance 90 cm on the other side of it. Name the kind of lens.
How will you differentiate between a convex and a concave lens by looking at a distant object.
The diagram showed a lens as a combination of one glass block and two prisms. Complete the ray diagram and show the part of the incident ray AB after passing through the lens.
(i) Name of the lens formed by the combination.
(ii) What is the line XX’ called?
(iii) Mark the focus F.
Complete the following diagram and state what happens to the ray of light after refraction through the lens.
Draw a ray diagram to show the image formed by a convex lens when the object is placed between F and 2F.
