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प्रश्न
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उत्तर
Focal length is the distance measured from the optical centre to the focus. The symbol for it is f.
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संबंधित प्रश्न
What is a lens?
Study the diagram shown in Fig. 5.56
Where is the image formed?
Study the diagram shown in Fig. 5.56
what are the two other characteristics of the image?
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) 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?
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.
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.
State the nature and position of the object on the principal axis to obtain a real and magnified image.
Draw a ray diagram to show the image formed by a convex lens when the object is placed between F and 2F.
