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प्रश्न
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उत्तर
Focal length (in metres) = `1/"power(in dioptres)"`
Focal length (in metres) = `1/2` = 0.5m = 50 cm
Since, the focal length is positive, the lens is aconvex lens.
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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) |
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.
State the condition of the following:
A lens has both its focal lengths equal.
(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.
Make the correct choices in the following items :
The image formed by a diverging lens, shown in fig, , is
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.
Complete the following diagram and state what happens to the ray of light after refraction through the lens.
Mixture of red + blue + green is passed through a convex lens as shown in the diagram below. State whether the ray passes through a single point or through different points on the principal axis after refraction.
