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प्रश्न
(a) Draw a sketch to show how a lens is able to produce an image of the sun on a paper screen.
(b)(i) Would you regard the rays from the sun as being divergent, parallel or convergent?
(ii) What is the name given to the point where such rays meet after they have passed through the lens?
(iii) How does the image of the sun sometimes burn a paper screen?
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उत्तर
(a)

(b)
(i) Rays from sun can be regarded as parallel rays.
(ii) The point is called 'Focus'.
(iii) A convex lens is used to focus the sun rays on a piece of paper to burn a piece of paper. A large amount of heat gets concentrated at a point and is sufficient to burn the piece of paper.
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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 ______.
Study the diagram shown in the following Figure.
Name the lens LL’ and draw its outline.

The diagram given below shows the position of an object OA in relation to a converging lens whose foci are at F1 and F2.

Describe three characteristic of the image.
A ray of light incident parallel to the principal axis of a lens, passes undeviated after refraction.
State the condition of the following:
A ray passes undeviated through 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.

Name the subjective property of light related to its wavelength.
Complete the following diagram and state what happens to the ray of light after refraction through the lens.

In the following diagram, L1 and L2 are the two convex lense placed at separation equal to the sum of focal lengths of the two lenses. A and B are the two rays of light incident on the lens L1. Complete the path of rays till they emerge out of the lens L2.

What principles have you used in completing the diagram?
Draw a ray diagram to show the image formed by a convex lens when the object is placed between F and 2F.
