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प्रश्न
State the condition when a lens is called an equi-convex or equi-concave.
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उत्तर
A lens is called an equiconvex or equiconcave when radii of curvature of the two surfaces of lens are equal.
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संबंधित प्रश्न
Explain optical centre of a lens with the help of proper diagram(s).
In the following figure (a) and (b), F1 and F2 are positions of the two foci of thin lenses. Draw the path taken by the light ray AB after it emerges from each lens.
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| (a) |
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| (b) |
Study the diagram shown in Fig. 5.56
Complete the diagram to show the formation of image A’B’ of the object AB of same size.
Study the diagram shown in Fig. 5.56
where is the object located?
Study the diagram shown in Fig. 5.56
Where is the image formed?
For an object placed at a distance 20 cm in front of a convex lens, the image is at a distance 20 cm behind the lens. The focal length of the convex lens is ______.
Make the correct choices in the following items :
The image formed by a diverging lens, shown in fig, , is
Fig. shows two rays of light Op and OQ coming from an object at the bottom of a pond, incident on the water surface.
(a) Mark on the diagram
(i) The angle of incidence of ray OP,
(ii) The angle of refraction of ray Op,
(iii) The position of image of the object as seen from above.
(iv) An approximate path of the ray OQ.
(b) Explain, why do the rays of light change directions on passing from water to air.
(c) A fish in water sees everything outside the water by rays of light entering its eye in a small cone of light. Draw a diagram and explain how does this happen.
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.
